Hosts are looking for tftp server.

  • Moderator

    @marted Well what I’m saying is if the fog server and the pxe booting computer is on the same subnet, then what I see in the pcap is non-standard.

    The standard dhcp/pxe boot is this.
    Client -> Discover
    DHCP -> Offer
    ProxyDHCP -> Offer
    Client -> Request
    DHCP -> ACK
    Client to ProxyDHCP -> Boot info request (udp port 4011)
    ProxyDHCP to Client -> Boot info (udp port 4011)
    Client -> TFTP server boot file size
    TFTP -> Client boot file size is
    Client -TFTP server give me file XXXX

    That is what I expect to see.

    Its possible that your dhcp-relay service is sending the off subnet dhcp offer via a unicast, in that case the fog server wouldn’t see it.

    BUT what I see in the pcap is
    Offer from proxy dhcp
    then right away another Discover from the client. This means it didn’t get an acceptable offer to give it an IP address.

    This is non-standard.

  • @george1421 the client takes IP from DHCP of the University. Me in the lab I use dnsmasq for proxy server. My server is configured like IP helper in the switch of my lab which has 4 subnet and 400 hosts. We have only one address NAT for all hosts 132.208… which address all hosts use for exit address. It works like router . DHCP of the University is on 132.208. and works fine it gives IP

    Exit address

  • @george1421 Ok , I’ll try tomorrow.
    It’s very very strange all this. Same hosts yesterday just one asked for TFTP server. Today 15 hosts ???
    With this config I use fog almost 4 months on different models HP and I saw one or two times to ask me for tftp server

  • Moderator

    @george1421 I still don’t understand why we don’t see an offer packet from your main dhcp server.

    What is your dhcp server?
    Is the pxe booting target computer on the same subnet as the fog server?
    What I see is a non-standard pxe boot. The client is getting an ip address from somewhere because its talking to the tftp server

  • Moderator

    @marted yes, exactly like in the tutorial

  • @george1421 do I have change it like this

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


  • Moderator

    @marted proxydhcp only provides pxe boot info not dhcp information. proxydhcp doesn’t care about subnets.

    What device is your main dhcp server?

  • @george1421 @Sebastian-Roth can I add some lines in my dnsmasq config which tells the tftp server. I think I saw that somewhere. I went today to other completely different lab with the same new model with new fog server I have just installed and I used the dnsmasq config like example to activate dhcp proxy and again the same problem, 40 hosts 15 ask for tftp server and when I enter it works.

  • @george1421 I need the dhcp range. I do pxe on 4 segments and

  • Moderator

    ok I see a few things.

    in the pcap

    1. I’m not seeing a offer from your main dhcp server, only the proxydhcp server (the fog server 149.43)
    2. In the offer from the proxydhcp server its sending the next server name but not the boot file name.
    3. I’m seeing a discover packet from 149.1 which seems to be a router via a dhcp-helper service?? The computer sending the discover appears to be reflecting back through the dhcp-helper service. Its a dell computer in uefi mode.

    in your dnsmasq configuration remove the subnet mask from the dhcp-range. You don’t want to enable other services on the dnsmasq service other than proxydhcp.

    I do see it strange that we don’t see an offer from your main dhcp server.

  • Developer

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


    The first thing jumping at me is the subnet mask. While it’s fine to do subnetting I am just wondering if you really intend to do this or if it’s a typo in the config?

    In the PCAP I can see some kind of DHCP relay answering as well - not exactly sure but it seems like it - IP

    There is some information missing in the PCAP file. This was probably captured on the FOG server, right? To actually understand your network and be able to help we need more information and possibly a capture taken from a different host (or monitoring port) in your network.

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