Subject: telnetd -u0 doesn't do what the manpage says.
To: None <email@example.com>
From: Stephen M Jones <firstname.lastname@example.org>
Date: 08/10/2001 01:28:34
I was happy to read in the telnetd manpage that:
-u len This option is used to specify the size of the field in the
utmp structure that holds the remote host name. If the re-
solved host name is longer than len, the dotted decimal val-
ue will be used instead. This allows hosts with very long
host names that overflow this field to still be uniquely
identified. Specifying -u0 indicates that only dotted deci-
mal addresses should be put into the utmp file.
However trying this, it seems telnetd is still consing (figurelatively
speaking) resolved IP address to pass on to /usr/bin/login -h
One of the mods I enjoyed doing under leenox was stripping out
hostname resolution from various daemons. I like the idea of having
a flag set which will allow this. It seems the hooks are in place,
but there is no real test/functionality just yet.
I did try looking into inetd to see if inetd is actually just passing
on resolved IPs to telnetd, and I don't believe it is.