If telnet doesn't enter a LOGIN entry in the utmp file,
login gets confused and adds a new entry at the end (even if
an entry for the tty already exists). This causes the utmp
file to keep growing as long as the system is up. A utmp
file over 1MB makes "who", "w", and other such programs slow
to a crawl on an active server.
I will send a patch for telnet that makes it create an entry
once I get a bug ID.
This appears similar to bug # 55. See the enclosed patch in the
Jeff: this has been fixed, right? If so we should close this.
And, finally, a better fix (to find utmp entry based on tty slot)
has been put into login.c that makes it unnecessary to create the
utmp entry before exec'ing login. Thanks for pointing this out.
Fix is in util-linux-2.9o-6.