mailing list archives
Re: Slow and Fast IP addresses on http ?
From: Paul Vixie <vixie () vix com>
Date: 17 Jun 2003 17:14:49 +0000
smb () research att com ("Steven M. Bellovin") writes:
It might also be port 113 -- some sites try to query your tcp port 113,
and wait for a timeout if the port is firewalled. A better solution
than blocking it is to send an immediate RST.
people who depend on tcp/113 deserve everything stupid that happens to them.
dropping SYN packets or returning a fixed string are both better than sending
an immediate RST. (false confidence being valued less than low confidence.)
i was rather shocked to discover tcp/113 clientness enabled by default in
postfix and sendmail. but even widespread ignorance does not call for
widespread coddling such as returning immediate RST's.