at our facility we use TFTP to allow diskless boot of our workstations, everything is fast and good :)

Now I'm prepraing to install Debian to muliple workstations, so I decided TFTP. I setup one test workstation, and modified DHCP:

host kmwil-deb1 {
            next-server IP_ADDRESS;
            filename "/kmwil/jessie/pxelinux.0";
            hardware ethernet aa:aa:aa:aa:aa:aa;
            fixed-address kmwil-deb1;

I downloaded Debian netboot installer and unpacked archive to the proper directory (file is accessible, chown to tftp, etc.).

PROBLEM: It takes about 5 minutes to see the Debian installer main screen. Machine gets address from DHCP, then TFPT.. shows, then PXELINUX Peter Anvin bla bla. This step takes about 5 minutes. I grep logs, this is the result.

TFTP download log

I tried curl the Debian archive from my tftp location and it took 15 seconds.

EDIT: 18:38

I read apropriate RFC and got tcpdump communication :) I observed multiple RRQ (Read Requests) for one file from client PC, from different ports. All of them were ACK. It looks like simultaneous RRQs? I also observed about 5 sec. timeouts between multiple RRQ and ACK from server. Don't know the reason for this yet.

I also setup virtual network with two hosts (Virtualbox), one as DHCP and TFTP server, second as pure client. Here installer loading is instantaneous. tcpdump is "clean", only one RRQ from single port, one ACK and no timeouts.

Best Regards,

  • did you know that, depending on the pxe software you use, you can use http rather than tftp to boot the debian installer? that's what i do on my pxe/tftp server. tftpd to serve just ipxe and then http from then on. ipxe.org
    – cas
    Commented Oct 28, 2015 at 10:10

1 Answer 1


5 seconds sounds like a DNS timeout. Maybe your TFTP server insists on resolving the IP address of the incoming requests, but the first name server in its /etc/resolv.conf does not answer to such requests? A full tcpdump trace of the server traffic could help.

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