TFTP Problems

Sebastian Roth

Ok I am going to format the linux and install it all over again.

But this won’t actually make PXE work for you. You need to get in contact with whoever is in charge for 10.1.8.254 and hopefully he’s willing to add options 66 and 67 for you.

bacelo

@Sebastian-Roth he already did and it still didn’t work

Sebastian Roth

Have you looked through this already? https://wiki.fogproject.org/wiki/index.php/Tftp_timeout

Start with sections on restarting tftp service and “Other Troubleshooting” (trying TFTP by hand)…

Either the TFTP on FOG server is not running properly OR the DHCP is not pointing to the correct IP address.

Wayne Workman

There’s this article too.

https://wiki.fogproject.org/wiki/index.php/Troubleshoot_TFTP

bacelo

I still haven’t got it working:(
The DHCP is being managed by the cisco device it is a quarentine network that is being maneged by some one other then me and I can only speak to him on the phone. So I am going to try to explain how I installed the fog server. So I followed this video: https://www.youtube.com/watch?v=QXHD-IQZigE
the only thing that I did different was the versions of the fog server.

george1421

Unfortunately, if your DHCP IP addresses are coming from this cisco device you are at the mercy of the owner of that dhcp server. No configuration that you can do with fog will help since the cisco dhcp server tells the client what to do next. Now if you want to pxe boot from a usb flash drive then you can regain some level of control and not need to make any dhcp server setting changes, but this will also require a special boot drive any time you want to boot into the pxe menu.

The other option is to shut off the dhcp relay between the network where the FOG server is and this other network, Then you will need to ensure that fog is setup to issue IP addresses for your local network. I see this as being a risky step because now FOG will supply all IP addresses for your side of the firewall.

bacelo

@george1421 how do I try the usb flash drive

bacelo

@george1421 and the thing that bugs me more is that they have this working in other schools. They say that they don’t have a firewall. And I don’t think that they will let me manege the dhcp

george1421

@bacelo said:

@george1421 and the thing that bugs me more is that they have this working in other schools. They say that they don’t have a firewall. And I don’t think that they will let me manege the dhcp

Are they unable to update the dhcp settings for you? All they need to do is to change dhcp settings 66 to point to the ip address of your fog server and dhcp option 67 to point to the boot file. That is all the action they need to do for your dhcp scope. Nothing else needs to be managed.

Wayne Workman

@george1421 said:

No configuration that you can do with fog will help since the cisco dhcp server tells the client what to do next.

There is dnsmasq. We have an article on it. I’ve used it extensively at home until I got confident with ISC-DHCP.

george1421

@Wayne-Workman I though you would know of a wiki for that.

Just off the top of your head, do you know of a wiki that talks about pxe booting from usb flash. I know how to do it for uefi, but not bios. If not I can work on a process tomorrow.

Wayne Workman

@george1421 There are several threads on it (only one worth anything). The wiki article on it is incredibly dated

Wayne Workman

@george1421 This is from 2009. I’ve tried this before and totally abandoned trying. https://wiki.fogproject.org/wiki/index.php/Bootable_Media

I started to mess around with using etherboot but never got anywhere with it.

george1421

The only issue I can see for dnsmasq is that the fog server is not on a subnet by itself. From what I think I understand the fog server is on the same network as the clients and the dhcp settings are coming from a remote location. Unless I’m off on this you can not run dnsmasq and dhcp-relay for the same subnet since both will respond to the dhcp request

Wayne Workman

https://forums.fogproject.org/topic/5587/bootable-usb-stick-v1-2-0/10

https://forums.fogproject.org/topic/4782/help-usb-boot-fog/10?page=2

Wayne Workman

@george1421 said:

The only issue I can see for dnsmasq is that the fog server is not on a subnet by itself. From what I think I understand the fog server is on the same network as the clients and the dhcp settings are coming from a remote location. Unless I’m off on this you can not run dnsmasq and dhcp-relay for the same subnet since both will respond to the dhcp request

You would run dnsmasq in proxy mode. It responds to DHCP Requests with only add-on information. It operates with a pre-existing DHCP server, it does not serve as a DHCP server.

https://wiki.fogproject.org/wiki/index.php/Using_FOG_with_an_unmodifiable_DHCP_server/_Using_FOG_with_no_DHCP_server

JJ Fullmer

Have you tried a proxy dhcp using dnsmasq like they’re talking about?

I do realize that you are using a redhat not a debian, so unless you switch to a debian flavor of linux like ubuntu server or what have you, the commands would be slightly different, but I’m pretty sure that there should be equivalents for this all in redhat if you don’t want to switch distros again, and I wouldn’t blame you at all.

I only know how to set it up on debian based linux with apt-get, but I imagine the yum RHEL package is probably the same name.
From what I recall to set it up…

sudo apt-get update
sudo apt-get install dnsmasq
sudo nano /etc/dnsmasq.d/ltsp.conf

In the ltsp.conf file put this…

port=0
log-dhcp
tftp-root=/tftpboot
dhcp-boot=undionly.kpxe,fog-server,10.1.8.1
dhcp-no-override
pxe-service=X86PC, "Boot from network", undionly
dhcp-range=10.1.8.1,proxy

You may need to make symlinks for dnsmasq to see the undionly file, and I’ve had some luck putting copies of the bootfile in the ipxe folder too, that very well may do nothing, but I think it fixed something once so I just kinda still do it to be safe since it doesn’t hurt anything.

sudo cp /tftpboot/undionly.kpxe /tftpboot/undionly.0
sudo cp /tftpboot/undionly.kpxe /var/www/fog/service/ipxe/undionly.kpxe
sudo cp /tftpboot/undionly.kpxe /var/www/fog/service/ipxe/undionly.0

Then restart the dnsmasq service (also do this whenever you make changes to this file)

sudo service dnsmasq restart

You can play with the dhcp-range value a bunch to try to get it to work. This is the method I used when I didn’t have access to the DHCP server.
You can try setting the range to just your FOG server’s ip. You can set it to the router gateway, you can set it to the dhcp server too. And you can try interchanging I’ve had some

In the event that enabling dnsmasq kills your resolvconf dns configuration (which it often does…) the easiest solution is to add your dns servers in /etc/resolvconf/resolv.conf.d/base
You would also want to edit /etc/resolvconf/interface-order to have your main network interface at the top. It defaults to local host first and makes it so 127.0.0.1 becomes your dns server and breaks the internet. At least it’s done that every time I’ve installed it on ubunutu.
so like this…

sudo nano /etc/resolvconf/resolv.conf.d/base

Then lets say you use google’s dns servers and google.com was your domain for a simple syntax example, you would do this…

nameserver 8.8.8.8
nameserver 8.8.4.4
search google.com

Then restart the resolvconf service

sudo service resolvconf restart

If that doesn’t take care of it and it is a problem, check out this forum post for more info
https://forums.fogproject.org/topic/2799/dnsmasq-kills-dns-lookup-on-fog-server/6

A basic rundown of my understanding of dnsmasq is this

Computer tries to boot to pxe and starts looking for the dhcp server
Your fog server pretends to be a dhcp server and beats the real dhcp server to it (If your fog server is on a slower switch than your dhcp server i.e a 100 Mbps port and the infrastructure is on a 10 Gbps port, then this might not work, I had that problem once)
The Dnsmasq service gives the computer the bootfile and uses the real dhcp server to get an ip address
You boot into pxe and do a happy dance

More information on dnsmasq and fog here https://wiki.fogproject.org/wiki/index.php/Using_FOG_with_an_unmodifiable_DHCP_server/Using_FOG_with_no_DHCP_server
and here https://wiki.fogproject.org/wiki/index.php/ProxyDHCP/dnsmasq-_DRAFT

Another option, albeit an extremely advanced and difficult option, is to set up fog as a tertiary dhcp server. You would have to look into configuring a linux dhcp server, not something I have personally done at that in depth of a level. Because you would have to figure out how to make it act as a separate vlan or something like that, or maybe just have a separate network for imaging rather than having it on your whole organization. Something like a switch and a workbench in your office. But those are just a couple fall back ideas.

Also a side note, @george1421 and @Wayne-Workman Wayne is right here. I’ve actually gotten dnsmasq to work on multiple subnets and buildings. Granted it was a complicated university environment, and I had to do some tricksy stuff. But don’t underestimate the power of dnsmasq.

Wayne Workman

@Arrowhead-IT Tagging your post for the #wiki -and I need to finish that article https://wiki.fogproject.org/wiki/index.php/ProxyDHCP_/_dnsmasq_-_DRAFT and I’ll likely use some of the stuff from that post below.

JJ Fullmer

@Wayne-Workman That makes me feel special Thanks

sportsdude11

Not sure if it was already mentioned, didnt see it in a quick scan but I had a similar issue. Make sure that DHCP Option 66 and 67 are enabled. 66 should be the IP address of your FOG server and 67 should be your undionly.kpxe file.

I struggled with it for a couple of hours, hopefully it helps you out.

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