Hi Michael, Michael <[email protected]> (2026-05-12): > # PROBLEM DESCRIPTION > > During installation, if automatic netowrk configuration is selected, the MTU > size provided by the DHCP server is not set. > > This is crucial if d-i runs in a virtual machine (Proxmox, qemu) which MTU > is set to a lower value than 1500 and thus results in an unaccessible > network connection when d-i tries to contact the repository server. Then, > wget hangs for a really, really long time and returns with an error and no > mirror is used. > > Circumventing this issue by manually setting desired MTU after configuring > the network (ip link dev <dev> set mtu <size>) works flawlessly. > > Also, there is no possibility to set the MTU size during manual network > configuration.
Did you try writing to /sys/class/net/<interface>/mtu? > # STEPS TO REPRODUCE > > Run d-i inside a vm (Proxmox, qemu) with a host's MTU size less than 1500. > > > # EXPECTED BEHAVIOR > > The MTU size provided by the DHCP server should be recognized and used to > configure the network. It seems busybox's udhcpc only supports a limited set of DHCP options, and MTU isn't on the list, from a quick look at common.h (commented out #defined) and common.c, which implement option parsing. Cheers, -- Cyril Brulebois ([email protected]) <https://debamax.com/> D-I release manager -- Release team member -- Freelance Consultant
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