nanog mailing list archives

Re: Verisign suggestion


From: Todd Vierling <tv () duh org>
Date: Thu, 18 Sep 2003 08:24:40 -0400 (EDT)


On Thu, 18 Sep 2003, David B Harris wrote:

: > ...and for heavens sake, stop accepting any kind of request at all on port
: > 25!! Just shut it down altogether. There is no reason for you to accept
: > any connection of any kind on port 25!

: If they don't accept anything on port 25, either by sending all packets
: to /dev/null or by responding with SYN+RST ("Connection refused"), MTAs
: everywhere will consider this a "temporary error."

Then the wildcard should have included a MX that points to nowhere, rather
than implementing a fake MTA that allows the MAIL FROM and RCPT TO addresses
to be transmitted.  The record "IN MX 0 ." is commonly used for this
purpose.

-- 
-- Todd Vierling <tv () duh org> <tv () pobox com>


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