---True, but in Arun's case he (I assume he, sorry) is trying to send mail to a hotmail user -- in this case you need do nothing at all.
yeah but that doesn't mean that the outside world will accept mail from
your server - a lot of systems want the mail server that is sending the
email to be resolvable via dns. That rule is pretty near to the top of
any list to control spam.
A lot of broken systems want the originating IP address to be resolvable via DNS (it's not recommended as a way of detecting spammers because of the low number of positives and the high number of false positives). In practice there are a heck of a lot of IP addresses that are perfectly valid but you can't do a sensible reverse look up on them ... what is far more common is checking the IP address against the "domestic" or "dynamically allocated" IP address ranges. My static, home IP address which be looked up in the DNS isn't acceptable to AOL, for example, because they claim it's dynamic (no one else does though).
Anyway, that doesn't cause failing connections. Arun's case looked, at first sight, as though sendmail was trying to connect directly to hotmail.com on port 25 and hotmail.com isn't listening, you have to connect to one of its MX hosts which suggested that Arun's DNS was hosed (though it could be a million and one other things).
If you can send mail but it bounces because the receiving host doesn't like your IP address, you just edit /etc/mail/sendmail.cf, look for the word "Smart" and put your ISP's mail relay on the next line. Oh, and restart sendmail. Couldn't be much easier, and I think it's documented in the Red Hat stuff, but it's been a while since I've looked.
jch
-- Shrike-list mailing list Shrike-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/shrike-list
