lars@newsone.org wrote:
hi,
my postfix is configured to reject incommimg traffic from unknown hosts. I found rejected traffic from an ip, which resolves to an official name, at least with nslookup <ipnum>. now when I do a reverse lookup, nslookup <hostname> it says domain not found. hostname beginns with digits and is therefore not rfc conform (?).
there is no point in rejecting mail from users (customers), with the message "hey, you got no DNS entry" when they come the other day telling me they got one (but not rfc conform), and if I dont accept it, they change to some other at the far end. but I do not want to relay spammers...
what is the background, and should I do something about it?
the world is evil. a host without a valid hostname or reverse lookup isn't really hard to get normaly, but many ppl. don't have. So if you reject mail from unknown hosts, you _may_ reject many legitimate mails. If you want to stop spam, try to use some dns rbl domains but be carefull with that. You can also write a script which will run every day (night) that parses the maillog and create some mails with informations why the mail was rejected (maybe also to the user who should recive the mail) -- intraDAT AG http://www.intradat.com Wilhelm-Leuschner-Strasse 7 Tel: +49 69-25629-0 D - 60329 Frankfurt am Main Fax: +49 69-25629-256 Junk mail is war. RFCs do not apply.