TFTP Problems

[Wayne Workman]

@bacelo

In case it helps clarify things - I’ll explain briefly how the network booting process works with FOG.

A DHCP service runs on some machine somewhere.

A host turns on… (This host is on the same network that DHCP is running on.)

Discovery
The host broadcasts to the network “Hey, I need an address.”

Offer
The DHCP service hears the broadcast, and then broadcast’s back “Here use this address and these options…”

Momentary pause
The host & server momentarily listen on the network for any objections from other hosts (a host with the same IP will broadcast “No you can’t use that, I already have it!”)

Request
The host then responds to the DHCP server with yet another broadcast and says “Ok, I want this address”.

Acknowledge
The server hears that and then responds with a broadcast saying “OK, you’ve got it, I’ve made note.”

So now… the HOST has an IP and configuration for that IP. The configuration (in FOG’s scenario) also contains DHCP Options 066 and 067. 66 is the “Next-Server” and 67 is the “Boot-file”. These options are sent out in the DHCP Offer (above).

The host will then ask the Next-Server for the Boot-File using TFTP.

The TFTP Server (usually the FOG server) will respond with the requested file.

And then other things begin happening… but you’re not getting even this far - you’re host isn’t getting an address from the FOG server, it’s getting an address from another DHCP server elsewhere - and THAT DHCP server is not configured correctly to hand out options 066 and 067.

Now then…

Hopefully you can see how having two DHCP Services on a network with one not configured will simply not work 100% of the time (and maybe none of the time). This is what @george1421 and @Sebastian-Roth were talking about. If there is a pre-existing DHCP Service running on the network, you need to edit that. We happen to have a full guide written just for doing this: https://wiki.fogproject.org/wiki/index.php/Modifying_existing_DHCP_server_to_work_with_FOG

[bacelo]

Ok , Yes the DHCP is not controlled by the fog server it is the network configuration it my be a router I am not sure. I do know that the DHCP server that hey are using in as it is in the Wiki fog page as it is for the cisco setup. Know sould I tell them to change the 10.1.8.254 to 10.1.8.1 will this help??

[george1421]

@bacelo said:

Ok , Yes the DHCP is not controlled by the fog server it is the network configuration it my be a router I am not sure. I do know that the DHCP server that hey are using in as it is in the Wiki fog page as it is for the cisco setup. Know sould I tell them to change the 10.1.8.254 to 10.1.8.1 will this help??

No what they have is fine, as long as you can set the options 66 and 67 for your 10.1.8.x scope to point to your FOG server and the boot file undionly.kxpe on that dhcp server. That is what’s missing here. That is why we are trying to figure out what 10.1.8.254 is.

[bacelo]

Ok I am going to format the linux and install it all over again. what version of linux do you recommend???

[Wayne Workman]

@bacelo Go with CentOS 7, or Fedora 23 Server.

For newcomers to Linux, you’ll be better off with CentOS because there is more documentation for it. It’s 100% Red Hat Enterprise Linux compatible, any commands that work with RHEL work with CentOS - and the RHEL / CentOS distros generally have about a 2 to 3 year lifecycle whereas Fedora has a 2 to 3 month life cycle.

I myself prefer Fedora, but CentOS 7 is rock solid.

But 1.2.0 won’t install on CentOS 7, you’ll need to use FOG Trunk. There’s article for it in the WiKi.

[Sebastian Roth]

@bacelo said:

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