FOG IP Address Change -- PxE Problems
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Hello all,
Due to us moving some of our servers to a different location we ended up changing our subnet for our servers in our main location (not my decision, my bosses). The FOG server stayed in this main location but the IP address has changed for it. I have changed the IP address in /opt/fog/.fogsettings and I also reran the installer. The Web Interface is working on the new address and I changed the IP addresses in there as well. When I try to PxE boot on a client to get into FOG it just errors out and says either it timed out or nothing was found (I can’t remember exactly what it says). I work remotely 10 hours away from the office so I will have to wait until Monday morning for someone to PxE boot and get the actual error message.
Just wondering if there’s anything I missed during the IP change?
Any help is appreciated! Thanks!
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@tlems Find information on IP change in our documentation: https://docs.fogproject.org/en/latest/reference/change_fog_server_ip_address.html
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@sebastian-roth This is where I first started. I did the above changes and it wasn’t working. I then did the script that WayneWorkman wrote to change the IP address to see if this did anything as well but that did not work either.
https://forums.fogproject.org/topic/9103/new-script-to-update-fog-server-s-ip-address -
@tlems Well, please post a picture of the error screen and we’ll surely find what’s wrong.
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@sebastian-roth Looks like TFTP is timing out. Everytime I try to upload the Picture or as a File I keep getting “Error” so here’s an imgur URL.
https://i.imgur.com/LrkYp1d.png
Should the DHCP be the IP of the FOG server? The old FOG server was at 10.0.0.95 but the DHCP is 10.0.0.30 which is something else completely different.
The IP of the new FOG server should be 10.2.2.16. When I shell into my FOG server and ifconfig it shows 10.2.2.16. -
@tlems said in FOG IP Address Change -- PxE Problems:
Should the DHCP be the name of the FOG server? The old FOG server was at 10.0.0.95 but the DHCP is 10.0.0.30 which is something else completely different.
DHCP and FOG server don’t have to be the same system. In some environments it is but it doesn’t have to be. We can’t tell you what it should be in your network. Sounds a bit like you have a rough DHCP server in your network (10.0.0.30). Please check to see if you can figure out who’s actually handing out this DHCP information.
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@sebastian-roth The 10.0.0.30 is our First Domain Controller. This was all set up from our old Network Administrator and we didn’t have problems until we switched IP’s. He’s not here anymore and FOG was placed into my hands. I’ve used FOG frequently but when it comes to setting up FOG and just settings in general, I’m brand new to it.
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@tlems said in FOG IP Address Change -- PxE Problems:
n-roth The 10.0.0.30 is our First Domain Controller.
Is it a Windows Server? Take a look at the DHCP settings and change DHCP option 66 to the new FOG server IP. Take a look at the information in this wiki article: https://wiki.fogproject.org/wiki/index.php?title=BIOS_and_UEFI_Co-Existence#Using_Windows_Server_2012_.28R1_and_later.29_DHCP_Policy
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@sebastian-roth Ahh!! You were correct there. Yes, our domain controller is on a Windows Server. The Policy in DHCP was still pointing to the old IP address. I changed the IP address to the correct one now. I’m guessing these changes aren’t immediate? I’ll try it in a little bit and see if there’s any progress.
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@sebastian-roth Work has slowed down a bit so I can fiddle with the FOG server again. I changed the IP’s in the Scope Options to the correct address but it still will not PxE boot. I have ipxe.efi for the filename and Bootfile name. Can you think of anything else that I am missing?
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@tlems Do you have a third computer where you can load wireshark on it. The computer needs to be connected to the same IP subnet as the pxe booting computer. In wireshark you want to setup a capture filter of
port 67 or port 68Start wireshark then immediately pxe boot the target computer. When you get the error on the target computer stop wireshark capture.In the capture you will see a discover packet from the target computer and one or more offer packets for each dhcp server that hears the discover.
Notable things in the discover is dhcp option 93 or 94 (can’t remember at the moment) will be the target computer saying what it is, 0 for bios and 7 or 9 for uefi.
In the offer from the dhcp server(s). In the ethernet header there will be {next-server} and {boot-file} for a uefi system the {boot-file} should be ipxe.efi and for [next-server} it should be the IP address of your fog server. If you look into the dhcp options 66 should be ip address of fog server and 67 the same as the {next-server} field. If they both look right confirm that dhcp option 60 is not being set (option should be absent in the offer).
If you can’t figure out the pcap then upload it to a file share site like google and either IM me or Sebastian the link or just post the link here and we will take a look at the pcap to see what we can see. The capture filter I mentioned above will only capture the dhcp process and no other data.
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@george1421 I’ll have to get this to you tomorrow as I’m currently home. I’ll PXE boot a machine and see what Wireshark brings up. Thanks!
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@tlems said in FOG IP Address Change -- PxE Problems:
I changed the IP’s in the Scope Options to the correct address but it still will not PxE boot.
Need more information. Error message on screen? Please post a picture.
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@george1421 So our FOG server is on a Hyper-V on CentOS within our Server Subnet. Then we have our Client subnet which is all of our associates machines. You want me to put this third computer within our server subnet and do a wireshark packet capture or on the Client network and do a packet capture?
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@tlems That would be on the client subnet. We need to see what the dhcp server(s) are telling the target computer. Since dhcp relies on broadcast messages we should be able to see the discover, offer, request, and ack packets. Now I do have to say I’ve seen some dhcp-relay services that switch over to unicast messaging on the client end. In this case we will only see the discover and request packets. But lets not go down that path just yet.
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@sebastian-roth The error message is the same as before that I posted earlier.
https://i.imgur.com/LrkYp1d.png -
@tlems said in FOG IP Address Change -- PxE Problems:
I posted earlier.
Just for reference, that screen shot is of a bios computer pxe booting. We are still down to understanding what the dhcp server is telling the pxe booting computer. The dhcp server is either telling the computer the wrong pxe boot address or boot file name. Its being told something because the error message says it can’t open the file and not, nothing was given.
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@george1421 I did a filter for both 67 and 68 and I didn’t get anything back (tcp.port eq 67) and I also did a search for the PxE booting machine’s ip address (ip.addr eq 10.0.2.217 and also did source ip.src eq 10.0.2.217 to see if I saw anything from this machine) and nothing matched my results in Wireshark. The ip address of the third machine I was using is 10.0.2.90 so they’re on the same subnet.
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@tlems the exact capture filter is “port 67 or port 68” if you captured everything then use a display filter of “bootp”. If you have one of us look at it be sure to use the capture filter so we don’t see things we shouldn’t in your capture.
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@george1421 Whoops, my bad. I got the capture filter set this time instead of doing a display filter. Also, when I sent the picture earlier I was replying back to Sebastian Roth’s comment. What’s the best way to send you the pcap file? I’m unable to upload it here.
