Hiho, the manpage of netmask still mentions software like ipchains, which is not part of any Debian release any more. AFAIR ipchains was Linux kernel 2.2, which latest version was released in 2005, and it's successor iptables introduced with kernel 2.4 in 2001 is now going to be replaced by nftables. Maybe it is time to remove this old piece of software from the manpage. Best regards, Martin