Hi, example-preseed.txt[1] contains the following:
+--- | #d-i netcfg/get_ipaddress string 192.168.1.42 | #d-i netcfg/get_netmask string 255.255.255.0 | [...] | #d-i netcfg/get_ipaddress string fc00::2 | #d-i netcfg/get_netmask string ffff:ffff:ffff:ffff:: +--- At least in the interactive mode of the installer one can instead specify the address as 192.168.1.42/24 or fc00::2/64 instead and won't get asked about the netmask. I think the example should use this notation instead, especially for non-legacy IP. (I've not verified it works with preseeding though.) I've not found where example-preseed.txt comes from; a quick grep through webwml.git did not find it. So I just write to this list :-) Ansgar [1]: https://www.debian.org/releases/stable/example-preseed.txt