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I used to deploy Debian 10 through PXE, and it worked.

Now that Debian 11 is released, I decided to do the same with it, but the installation fails as soon as it tries to configure the network:

Network autoconfiguration failed

Your network is probably not using the DHCP protocol. Alternatively, the DHCP server may be slow or some network hardware is not working properly.

There are a few strange things:

  1. The machine can reach DHCP when it just loads. I can see the DHCPDISCOVER, DHCPOFFER, DHCPREQUEST, and DHCPACK messages in the log in DHCP server. Besides, the machine communicates with the TFTP server (to retrieve pxelinux.0 and others) using its correct IP address. So, after all, the machine does access DHCP, and gets access to the local network, but then magically forgets about it.

  2. The machine has two adapters: enp1s0 and enp111s0. If during the installation, I bring the console and I ip link set enp111s0 down; ip addr add 192.168.1.50/24 dev enp1s0, then I can access the local network (but not internet).

  3. If, additionally, I specify a gateway by running ip route add default via 192.168.1.1 dev enp1s0, I can access not only the local network, but internet as well.

What happened in Debian 11 which could explain that?

How can I fix the connectivity issue?

Arseni Mourzenko
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1 Answers1

3

Found it, although I'm still not sure why this happened.

  1. The machine has two network adapters, but only one is (and always was) used during the installation (the other one is unplugged).

  2. Debian 11 somehow decided that it should use enp111s0, which happens to be unplugged, and ignoring enp1s0 despite the fact that it would work.

  3. The solution is therefore to change pxelinux.cfg to force Debian to use enp1s0, so instead of:

    # D-I config version 2.0
default linux
label linux
kernel debian-installer/amd64/linux
append [...] netcfg/choose_interface=auto --

    I now have:

    # D-I config version 2.0
default linux
label linux
kernel debian-installer/amd64/linux
append [...] netcfg/choose_interface=enp1s0 --

This works: the installation is launched successfully. This being said, I'm still wondering why Debian 10 had a different behavior, and would be happy to accept an answer which would provide some information about this.

Arseni Mourzenko
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