Hosts are looking for tftp server.

[marted]

@george1421 Yes, all of them. Next time when I stop the hosts and started with wake up on LAN now other 10-15 ask for tftp server, always in the same room of 25 hosts

[marted]

@george1421 if I just press enter without entering tftp server it gives this

Same host on the next boot

[marted]

@george1421 now one more thing - when I boot manually host by host with F12 every host boot correctly with no problems. The problem come only when I try to boot them all with a task and wake up on LAN. I have impression that there is a limit of hosts to connect to tftp server simultaneously at the same time. this is a new model very fast with i7 8th Gen , 1 Tb SSD and it boot for few seconds.

[george1421]

@marted Well let me say that iPXE is working exactly as it was programmed to do. If it doesn’t receive pxe boot information from either the dhcp server or a proxydhcp server then it will prompt the user.
ref: https://github.com/FOGProject/fogproject/blob/master/src/ipxe/src/ipxescript

This is a dhcp (proxydhcp) issue and not anything to do with tftp. If it was a tftp issue the iPXE boot loader would not be running on the target computer asking for a boot server.

Along the lines of a random dhcp issue, that can come from having two or more dhcp servers on your campus that have different configuration for the subnets. Where the first dhcp server that responds wins the election. Now that a proxydhcp server is involved, if the proxydhcp server doesn’t respond in time to too late the client will not use (or have) any pxe boot information.

I’ll ask the question again, is the computer that is showing this random ask for tftp server on the same subnet as the fog server? If so then there is something wrong with the proxy dhcp process because since its on the local subnet as the pxe booting computer it should hear the discover every time (the first pcap was showing that). What I did not see in the first pcap was the main dhcp server responding. Based on what I’m seeing in the pcap I would say the main dhcp is either responding sluggishly or random dhcp servers are in play.

If the target computer is on a different subnet, then you will need to load wireshark on a witness computer with the capture filters that Sebastian provided. This will only allow us to see the dhcp process, but at least we can see what actors are involved here.

IMO the issue at the moment is an network infrastructure one and not anything to do with FOG, other than we need network booting to work to get FOG to work. Since we don’t know your networking infrastructure we can only make suggestions where to look based on our experiences and intimately knowing how FOG works.

[marted]

@george1421 @Sebastian-Roth you’re right. This is a issue of the dnsmasq (DHCP proxy server) not FOG. If you want change the place of the topic.
The Dnsmasq is not capable to handle many requests at a time. All tests I made Yesterday I found that up to 10-12 computers at a time there is no issues. Like I said earlier in my posts, the problem is ONLY with this new model we have, because they boot simultaneously and I guess almost all at the same time ‘‘ask’’ the proxy dhcp for information. Like you said if the proxy is not capable to handle the request for a host, this host will pass to the next dhcp in the network, and because we don’t have 3th one dhcp in the network, it will return to the main dhcp (DHCP of the University) . We see this request in the wireshark file like a request on the exit IP 192.168.148.1 and answer from it.
Now the question is how to fix this situation. In this close private network we have 10 rooms each room with 25 computers, all of them (250) installed on 4 sub net 192.168.148.0, 192.168.149.0 192.168.150.0 192.168.151.0. The server FOG is a virtual server fixed on 192.168.149.43 and configured on our private switch in the lab like an IP Helper (DHCP proxy). Up to now almost 5 months, no issues with FOG for booting. Like I said this is the first time we have a problem like this, simply because in other rooms the old models, when I send a task for 25 hosts they don’t wake up on LAN exactly in the same time, and because of that they don’t '‘ask’ dhcp proxy for information in the same time. Now the new model hosts I see it do that.
My questions (I am just asking I don’t know the question is correct or no )
Is it possible to setup the dnsmasq to handle requests one at a time and like this to be able to proceed all requests?
Can we have second port open to handle part of the requests?
or second dnsmasq on the same server?
or second server only with dnsmasq installed which will transfer only the information which leads to the real FOG server?
or getting(install) better network card?
If you have some other suggestion I am open to listen.
I know it is always possible just to boot the hosts one at a time with F12 and it will work a 100% or make small groups of 5-10 hosts for this model, but I like very much the way FOG can handle many hosts at a time and.
Another thing I turnoff all hosts in the evening and when I wake up on LAN room by room in the morning just in this room I have to go and reboot again manually or enter tftp server info.
I hope to find some solution!
Thanks again for all your help

[Sebastian Roth]

@marted That’s an interesting one. From what you describe it really sounds as if dnsmasq is not able to serve all of them at the same time. If that’s the case we should be able to see this in the logs. First figure out which log file is used: grep "dnsmasq" /var/log/messages /var/log/syslog /var/log/daemon.log

Depending on the Linux OS you have the logging might be in a different file. When you have found it schedule a deploy task for those Dell AIO 7470 hosts and run tail -f /var/log/syslog | grep "dnsmasq" | tee /tmp/dnsmasq.log to see all the log messages coming in life as well as save those to a separate log file in /tmp/dnsmasq.log.

Together with a lost of MAC addresses of the Dell AIO 7470 hosts and the log file you should be able to see which one got the PXE/TFTP information and which didn’t on that run. Maybe there are hints in the log that one was skipped. Not sure. Upload the log file here if you need help with finding anything in it.

[marted]

@Sebastian-Roth I got the log file dnsmasq.log
This are the MAC addresses which asked for tftp server
00:4e:01:c5:f4:67
00:4e:01:c5:fa:98
00:4e:01:c5:e7:c4
00:4e:01:c5:a5:9a

[Sebastian Roth]

@marted Well done!

First thing I notice is that we see pretty much every request coming in twice in the logs. Makes me wonder if this might confuse the clients as they probably get two responses from that as well. Probably these duplicated messages come from the IP helper?!

Though it’s interesting you get a 100% success rate on PXE booting when it’s not a multicast.

As well further down in the log we see it repeat the same log messages three times before it goes on to actually send out the information:

Mar  9 12:55:47 foglabunix dnsmasq-dhcp[744]: 1635745377 available DHCP subnet: 192.168.149.43/255.255.252.0
Mar  9 12:55:47 foglabunix dnsmasq-dhcp[744]: 1635745377 vendor class: PXEClient:Arch:00007:UNDI:003010
Mar  9 12:55:47 foglabunix dnsmasq-dhcp[744]: 1635745377 user class: iPXE
Mar  9 12:55:47 foglabunix dnsmasq-dhcp[744]: 1635745377 available DHCP subnet: 192.168.149.43/255.255.252.0
Mar  9 12:55:47 foglabunix dnsmasq-dhcp[744]: 1635745377 vendor class: PXEClient:Arch:00007:UNDI:003010
Mar  9 12:55:47 foglabunix dnsmasq-dhcp[744]: 1635745377 user class: iPXE
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 available DHCP subnet: 192.168.149.43/255.255.252.0
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 vendor class: PXEClient:Arch:00007:UNDI:003010
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 user class: iPXE
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 PXE(ens32) 00:4e:01:c6:36:08 proxy
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 tags: UEFI, ens32
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 bootfile name: ipxe.efi
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 server name: 192.168.149.43
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 next server: 192.168.149.43
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 sent size:  1 option: 53 message-type  5
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar  9 12:55:48 foglabunix dnsmasq-dhcp[744]: 1635745377 sent size: 17 option: 97 client-machine-id  ...

See if you can figure out why all the DHCP messages seem to be duplicates in your network. This might be the key. Not sure though but it’s still worth looking at and fixing it.

[marted]

@Sebastian-Roth said in Hosts are looking for tftp server.:

grep “dnsmasq” /var/log/

I have just seen the tftpd log and something is wrong. See the time I test today two times

root@foglabunix:/var/log# systemctl status tftpd-hpa
● tftpd-hpa.service - LSB: HPA's tftp server
   Loaded: loaded (/etc/init.d/tftpd-hpa; generated)
   Active: active (running) since Mon 2020-03-09 12:13:55 EDT; 2h 2min ago
     Docs: man:systemd-sysv-generator(8)
  Process: 1473 ExecStart=/etc/init.d/tftpd-hpa start (code=exited, status=0/SUCCESS)
    Tasks: 1 (limit: 4915)
   CGroup: /system.slice/tftpd-hpa.service
           └─1509 /usr/sbin/in.tftpd --listen --user root --address :69 -s /tftpboot

Mar 09 12:55:51 foglabunix in.tftpd[3843]: tftp: client does not accept options
Mar 09 12:55:51 foglabunix in.tftpd[3845]: tftp: client does not accept options
Mar 09 12:55:51 foglabunix in.tftpd[3849]: tftp: client does not accept options
Mar 09 12:55:51 foglabunix in.tftpd[3851]: tftp: client does not accept options
Mar 09 12:55:51 foglabunix in.tftpd[3853]: tftp: client does not accept options
Mar 09 13:24:03 foglabunix in.tftpd[6395]: tftp: client does not accept options
Mar 09 13:24:03 foglabunix in.tftpd[6406]: tftp: client does not accept options
Mar 09 13:24:03 foglabunix in.tftpd[6419]: tftp: client does not accept options
Mar 09 13:24:03 foglabunix in.tftpd[6421]: tftp: client does not accept options
Mar 09 13:24:03 foglabunix in.tftpd[6432]: tftp: client does not accept options

and all log from today

Mar  9 11:34:40 foglabunix in.tftpd[10796]: tftp: client does not accept options
Mar  9 11:35:35 foglabunix in.tftpd[10979]: tftp: client does not accept options
Mar  9 12:24:07 foglabunix in.tftpd[14779]: tftp: client does not accept options
Mar  9 12:25:07 foglabunix in.tftpd[14950]: tftp: client does not accept options
Mar  9 12:33:42 foglabunix in.tftpd[15559]: tftp: client does not accept options
Mar  9 12:13:55 foglabunix tftpd-hpa[1473]:  * Starting HPA's tftpd in.tftpd
Mar  9 12:13:55 foglabunix tftpd-hpa[1473]:    ...done.
Mar  9 12:39:34 foglabunix in.tftpd[2389]: tftp: client does not accept options
Mar  9 12:39:36 foglabunix in.tftpd[2391]: tftp: client does not accept options
Mar  9 12:39:36 foglabunix in.tftpd[2393]: tftp: client does not accept options
Mar  9 12:39:36 foglabunix in.tftpd[2395]: tftp: client does not accept options
Mar  9 12:39:44 foglabunix in.tftpd[2411]: tftp: client does not accept options
Mar  9 12:39:44 foglabunix in.tftpd[2413]: tftp: client does not accept options
Mar  9 12:39:44 foglabunix in.tftpd[2415]: tftp: client does not accept options
Mar  9 12:39:44 foglabunix in.tftpd[2417]: tftp: client does not accept options
Mar  9 12:39:44 foglabunix in.tftpd[2419]: tftp: client does not accept options
Mar  9 12:39:45 foglabunix in.tftpd[2421]: tftp: client does not accept options
Mar  9 12:40:05 foglabunix in.tftpd[2455]: tftp: client does not accept options
Mar  9 12:40:05 foglabunix in.tftpd[2457]: tftp: client does not accept options
Mar  9 12:40:05 foglabunix in.tftpd[2458]: tftp: client does not accept options
Mar  9 12:40:05 foglabunix in.tftpd[2461]: tftp: client does not accept options
Mar  9 12:40:05 foglabunix in.tftpd[2462]: tftp: client does not accept options
Mar  9 12:55:41 foglabunix in.tftpd[3796]: tftp: client does not accept options
Mar  9 12:55:41 foglabunix in.tftpd[3798]: tftp: client does not accept options
Mar  9 12:55:41 foglabunix in.tftpd[3800]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3815]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3817]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3819]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3821]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3823]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3825]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3826]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3827]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3831]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3833]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3834]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3837]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3838]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3840]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3843]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3845]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3847]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3849]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3851]: tftp: client does not accept options
Mar  9 12:55:51 foglabunix in.tftpd[3853]: tftp: client does not accept options
Mar  9 12:56:12 foglabunix in.tftpd[3890]: tftp: client does not accept options
Mar  9 13:02:59 foglabunix in.tftpd[4521]: tftp: client does not accept options
Mar  9 13:04:02 foglabunix in.tftpd[4599]: tftp: client does not accept options
Mar  9 13:23:53 foglabunix in.tftpd[6370]: tftp: client does not accept options
Mar  9 13:23:53 foglabunix in.tftpd[6372]: tftp: client does not accept options
Mar  9 13:23:53 foglabunix in.tftpd[6374]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6394]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6395]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6398]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6401]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6400]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6402]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6406]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6408]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6409]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6411]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6413]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6416]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6418]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6419]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6421]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6424]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6426]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6428]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6430]: tftp: client does not accept options
Mar  9 13:24:03 foglabunix in.tftpd[6432]: tftp: client does not accept options
Mar  9 13:24:24 foglabunix in.tftpd[6479]: tftp: client does not accept options
Mar  9 13:24:33 foglabunix in.tftpd[6490]: tftp: client does not accept options
Mar  9 13:25:35 foglabunix in.tftpd[6553]: tftp: client does not accept options
Mar  9 13:31:52 foglabunix in.tftpd[7174]: tftp: client does not accept options
Mar  9 13:32:53 foglabunix in.tftpd[7241]: tftp: client does not accept options
Mar  9 13:52:48 foglabunix in.tftpd[9009]: tftp: client does not accept options

[Sebastian Roth]

@marted said in Hosts are looking for tftp server.:

tftp: client does not accept options

As far as I know this is ok. It means that the client requests the size and TFTP server just says it doesn’t support querying size. I have seen this often. Should not cause a problem.

Have you looked at why DHCP queries come in duplicated?

[marted]

@Sebastian-Roth said in Hosts are looking for tftp server.:

Have you looked at why DHCP queries come in duplicated?

I have no idea. I looked in the config file. Nothing different than your example in wiki. I’ll make today a test with tcpdump on 69 to see the traffic info on the server. Also I’ll check this options in dnsmasq like:

--tftp-no-fail
Do not abort startup if specified tftp root directories are inaccessible.
--tftp-max=<connections>
Set the maximum number of concurrent TFTP connections allowed. This defaults to 50. When serving a large number of TFTP connections, per-process file descriptor limits may be encountered. Dnsmasq needs one file descriptor for each concurrent TFTP connection and one file descriptor per unique file (plus a few others). So serving the same file simultaneously to n clients will use require about n + 10 file descriptors, serving different files simultaneously to n clients will require about (2*n) + 10 descriptors. If --tftp-port-range is given, that can affect the number of concurrent connections.
--tftp-no-blocksize
Stop the TFTP server from negotiating the "blocksize" option with a client. Some buggy clients request this option but then behave badly when it is granted.
--tftp-port-range=<start>,<end>
A TFTP server listens on a well-known port (69) for connection initiation, but it also uses a dynamically-allocated port for each connection. Normally these are allocated by the OS, but this option specifies a range of ports for use by TFTP transfers. This can be useful when TFTP has to traverse a firewall. The start of the range cannot be lower than 1025 unless dnsmasq is running as root. The number of concurrent TFTP connections is limited by the size of the port range.

I’ll try also to capture a log with a different model clients to see if there is a différents.

[george1421]

@Sebastian-Roth said in Hosts are looking for tftp server.:

Have you looked at why DHCP queries come in duplicated?

I think I can explain this (or at least make up something that sounds good).

What I saw in a previous pcap on this issue was with the target computer on the same subnet as the FOG server (running dnsmasq) but the main dhcp server is on a different subnet. When the target issued a DHCP discover, there was an OFFER from dnsmasq (as it should) but there was also an OFFER from the dhcp-helper service on the subnet router. This OFFER from the dhcp-helper service was a reflection of the dhcp OFFER from dnsmasq.

(educated guess follows) The dhcp-helper service is configured to listen on the interface where the fog server is as well as the target computer. It is configured this way to allow the remote dhcp server to reply dhcp requests on the local subnet. This is standard and typical. Now for dnsmasq to reply with pxe boot information for remote subnets we would typically add the dnsmasq server as the last server in the dhcp-helper service. This would then inform the dnsmasq server when a client was pxe booting on a remote subnet. The problem comes where the dhcp-helper service is listening on the same subnet where the dnsmasq server is. The dnsmasq server replies to the OFFER directly to the target computer, but the dhcp-helper service also hears the DISCOVER and as its programmed sends to the DISCOVER to dnsmasq where it replies to the dhcp-helper service which then echos the OFFER from dnsmasq back to the target computer generating 2 offers from the same service (dnsmasq) from only one DISCOVER request.

[george1421]

@marted said in Hosts are looking for tftp server.:

The Dnsmasq is not capable to handle many requests at a time.

Its possible on a really busy FOG server that dnsmasq doesn’t have enough time to respond to all of the requests, but I find that a bit hard to believe. You could try to move dnsmasq to a standalone linux server to see if it helps. But I don’t think the speed of dnsmasq is your issue here.

While its not a clean solution you could place a dnsmasq server on each of the 4 subnets and then remove the fog server from the dhcp-helper service. Each dnsmasq server on each subnet would be responsible for providing the pxe boot information for just that subnet. Just thinking out of the box, but a raspberry pi running raspbian would work for the dnsmasq server on each subnet. A standalone VM (not the fog server) with dnsmasq running with an interface on each subnet would also work.

[marted]

@george1421 said in Hosts are looking for tftp server.:

VM (not the fog server) with dnsmasq running with an interface on each subnet would also work.

Wow @george1421 very useful information. Now how to make an interface on each subnet in one dnsmasq? add info in the same config file or crate 4 different config files. Could you help me with that?
Why we just not use the integrated tftp server with dnsmasq with the option enable-tftp and give the dnsmasq informaiton that we accept requests from 4 subnet?

[george1421]

@marted said in Hosts are looking for tftp server.:

Now how to make an interface on each subnet in one dnsmasq? add info in the same config file or crate 4 different config files. Could you help me with that?

Understand this is on a new server not fog. But just create a new server with 4 interfaces. Place each interface on each subnet. There is only one config file because there is no reference to any subnet or mask in the config file. Make sure that the dhcp-helper service forgets about dnsmasq because everything will be handled locally. Once the server is setup, if we have to, we could create and install 4 instances of dnsmasq each bound to a different subnet and each with its own config file. But I don’t think that is necessary. One instance and one config file should be enough.

[marted]

@george1421 @Sebastian-Roth now before start creating 4 interfaces I made some changes and it gives some results.
First I delete the server form IP Helper in the private switch and on the DHCP of the University we configured the server like a tftp-server. Means once the client contact the DHCP for IP will take the information for the tftp server. This one I think solved the problem of multi requests in the network but did not solve the problem with the hosts which ask for tftp server.
Second I changed a little bit the config of dnsmasq. I replaced 192.168.149.43,proxy with

dhcp-range=192.168.148.0,proxy
dhcp-range=192.168.149.0,proxy
dhcp-range=192.168.150.0,proxy

and now i have only 3 or 4 client ask for tftp. Only with the first changes and no changes in dnsmasq i had still 10 posts asking for tfpt server

This is a part of the log now from dnsmsaq log.

Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3819419945 next server: 192.168.149.43
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3819419945 broadcast response
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3819419945 sent size:  1 option: 53 message-type  2
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3819419945 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3819419945 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3819419945 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:38:80:31:c3:c0:4f...
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 PXE(ens32) 00:4e:01:c6:11:fc proxy
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 tags: UEFI, ens32
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 next server: 192.168.149.43
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 broadcast response
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 sent size:  1 option: 53 message-type  2
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3434271658 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:37:80:57:c3:c0:4f...
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 PXE(ens32) 00:4e:01:c6:35:9e proxy
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 tags: UEFI, ens32
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 next server: 192.168.149.43
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 broadcast response
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 sent size:  1 option: 53 message-type  2
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 3095135073 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:37:80:59:c3:c0:4f...
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 2455006384 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 2455006384 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 2455006384 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 2455006384 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 2455006384 vendor class: MSFT 5.0
Mar 10 12:51:57 foglabunix dnsmasq-dhcp[31581]: 2455006384 client provides name: C39986.ens.uqam.ca
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 PXE(ens32) 00:4e:01:c5:f4:67 proxy
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 tags: UEFI, ens32
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 next server: 192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 broadcast response
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 sent size:  1 option: 53 message-type  2
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2108649736 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:43:80:56:c3:c0:4f...
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 PXE(ens32) 00:4e:01:c5:eb:ab proxy
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 tags: UEFI, ens32
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 next server: 192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 broadcast response
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  1 option: 53 message-type  2
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:42:80:56:c3:c0:4f...
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 PXE(ens32) 00:4e:01:c6:2b:3f proxy
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 tags: UEFI, ens32
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 next server: 192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 broadcast response
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  1 option: 53 message-type  2
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:37:80:56:c3:c0:4f...
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 PXE(ens32) 00:4e:01:c5:e7:6d proxy
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 tags: UEFI, ens32
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 next server: 192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 broadcast response
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 sent size:  1 option: 53 message-type  2
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 648478975 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:43:80:5a:c3:c0:4f...
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 PXE(ens32) 00:4e:01:c6:25:55 proxy
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 tags: UEFI, ens32
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 next server: 192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 broadcast response
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  1 option: 53 message-type  2
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 153622816 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:48:80:31:c3:c0:4f...
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 PXE(ens32) 00:4e:01:c6:12:2d proxy
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 tags: UEFI, ens32
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 next server: 192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 broadcast response
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 sent size:  1 option: 53 message-type  2
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 sent size:  4 option: 54 server-identifier  192.168.149.43
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 sent size:  9 option: 60 vendor-class  50:58:45:43:6c:69:65:6e:74
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 1703402172 sent size: 17 option: 97 client-machine-id  00:44:45:4c:4c:32:00:10:37:80:33:c3:c0:4f...
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2521786052 available DHCP subnet: 192.168.148.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2521786052 available DHCP subnet: 192.168.149.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2521786052 available DHCP subnet: 192.168.150.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2521786052 available DHCP subnet: 192.168.151.0/255.255.252.0
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2521786052 vendor class: PXEClient:Arch:00007:UNDI:003016
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2521786052 PXE(ens32) 00:4e:01:c6:26:86 proxy
Mar 10 12:52:01 foglabunix dnsmasq-dhcp[31581]: 2521786052 tags: UEFI, ens32

[Sebastian Roth]

@marted @george1421 Nice things you guys worked out. I am at a loss with this. Can’t really believe that dnsmasq is not able to respond to 20 clients “at the same time”. Though I don’t have a really good idea on how to tackle this issue.

Well here is one other thing you can try. Check to see if the switch you have all the clients hooked to with some running into the issue. See if you can setup a port mirror to receive all the communication from one (or a couple) of the client port on a mirror port. Hook up a laptop/PC to that mirror port, assign a static IP to it (doesn’t matter which because we don’t need it to comuinicate with the network, we just want to make sure it does not send out DHCP requests itself). Install wireshark and capture all the traffic up to the point where you have DHCP information captures with hosts that show the “enter tftp” message. Now filter the wireshark capture to only see information with that MAC address. I would be really interested to actually see what DHCP information it received.

[marted]

@george1421
I created 4 interfaces

inet 192.168.149.43/22 brd 192.168.151.255 scope global dynamic noprefixroute ens32
    inet 192.168.148.254/22 brd 192.168.151.255 scope global eth10:0
    inet 192.168.149.254/22 brd 192.168.151.255 scope global eth11:0
    inet 192.168.150.254/22 brd 192.168.151.255 scope global eth12:0
    inet 192.168.151.254/22 brd 192.168.151.255 scope global eth13:0

I changed the dnsmasq conf like this

dhcp-range=eth10,192.168.148.254,proxy
dhcp-range=eth11,192.168.149.254,proxy
dhcp-range=eth12,192.168.150.254,proxy
dhcp-range=eth13,192.168.151.254,proxy

but nothing changed, I mean I still have 5 to 7 posts asking for tftp server.
Could you check the config. Maybe I missed something.

dnsmasq status

root@foglabunix:/var/log# clear
root@foglabunix:/var/log# nano /etc/dnsmasq.d/ltsp.conf
root@foglabunix:/var/log# nano /etc/dnsmasq.d/ltsp.conf
root@foglabunix:/var/log# systemctl status dnsmasq
● dnsmasq.service - dnsmasq - A lightweight DHCP and caching DNS server
   Loaded: loaded (/lib/systemd/system/dnsmasq.service; enabled; vendor preset: enabled)
   Active: active (running) since Tue 2020-03-10 13:35:28 EDT; 10min ago
  Process: 4589 ExecStop=/etc/init.d/dnsmasq systemd-stop-resolvconf (code=exited, status=0/SUCCESS)
  Process: 4606 ExecStartPost=/etc/init.d/dnsmasq systemd-start-resolvconf (code=exited, status=0/SUCCESS)
  Process: 4597 ExecStart=/etc/init.d/dnsmasq systemd-exec (code=exited, status=0/SUCCESS)
  Process: 4596 ExecStartPre=/usr/sbin/dnsmasq --test (code=exited, status=0/SUCCESS)
 Main PID: 4605 (dnsmasq)
    Tasks: 1 (limit: 4915)
   CGroup: /system.slice/dnsmasq.service
           └─4605 /usr/sbin/dnsmasq -x /run/dnsmasq/dnsmasq.pid -u dnsmasq -7 /etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new --local-service --trust-anchor=.,19036,8,2,49aac11d7b6f6446702e54a16073

Mar 10 13:46:06 foglabunix dnsmasq-dhcp[4605]: 2327500257 available DHCP subnet: 192.168.150.254/255.255.252.0
Mar 10 13:46:06 foglabunix dnsmasq-dhcp[4605]: 2327500257 available DHCP subnet: 192.168.151.254/255.255.252.0
Mar 10 13:46:06 foglabunix dnsmasq-dhcp[4605]: 2327500257 vendor class: MSFT 5.0
Mar 10 13:46:06 foglabunix dnsmasq-dhcp[4605]: 2327500257 client provides name: C42145
Mar 10 13:46:10 foglabunix dnsmasq-dhcp[4605]: 2327500257 available DHCP subnet: 192.168.148.254/255.255.252.0
Mar 10 13:46:10 foglabunix dnsmasq-dhcp[4605]: 2327500257 available DHCP subnet: 192.168.149.254/255.255.252.0
Mar 10 13:46:10 foglabunix dnsmasq-dhcp[4605]: 2327500257 available DHCP subnet: 192.168.150.254/255.255.252.0
Mar 10 13:46:10 foglabunix dnsmasq-dhcp[4605]: 2327500257 available DHCP subnet: 192.168.151.254/255.255.252.0
Mar 10 13:46:10 foglabunix dnsmasq-dhcp[4605]: 2327500257 vendor class: MSFT 5.0
Mar 10 13:46:10 foglabunix dnsmasq-dhcp[4605]: 2327500257 client provides name: C42145
lines 1-22/22 (END)

[george1421]

@marted I can’t speak for this setting since I’ve never used it.

dhcp-range=eth10,192.168.148.254,proxy
dhcp-range=eth11,192.168.149.254,proxy
dhcp-range=eth12,192.168.150.254,proxy
dhcp-range=eth13,192.168.151.254,proxy

I can say for 99% of the dnsmasq installs this line is all that is needed.

dhcp-range=<fog_server_IP>,proxy

Just for clarity this is a new vm and not the fog server where dnsmasq is installed?

So if you are on a subnet where these 5-7 workstations ask for the tftp server. If you have wireshark loaded on a third computer with the capture filter of port 67 or port 68 do you only see one or 2 offers? There has to be still something else going on here. Dnsmasq should be fast enough to respond to 100s of requests per second.

[marted]

@george1421 @Sebastian-Roth
Please somebody to help me with the options 66 67
on windows DHCP (Infoblox). Finally the University accepted to add the info for tftp on the main dhcp and like this I can stop the dnsmasq.
On 66 I put the IP of the server 192.168.149.43
but on 67 I don’t know how to provide the syntax of the boot file. Do I have to write /tftpboot/default.ipxe or I write directly default.ipxe
Thanks