[Mimedefang] OT - Using rDNS sendmail hack - your experiences

James Ebright jebright at esisnet.com
Wed Apr 27 16:36:17 EDT 2005


On Wed, 27 Apr 2005 15:14:20 -0400, Jason Gurtz wrote

> If you do strict reverse checking you'll definitely throw out valid mail.
>  You'll just have to see if that's OK or how much BOFH you can get 
> away with.

Niel's hack only tempfails in the scenario where there is a PTR but it does
not match.... This gives our admin staff alot of time to decide to whitelist
or to take other actions, so far we have whitelisted one local ISP from rDNS
checks and one local business that is working on correcting their issues (more
numerous than just rDNS).

Honestly, in your case I would use CNAMES liberally and make your MX server
the same as the PTR reverses but have customers still use the CNAME for their
MUA configurations. This will not appear any different to the end user but
will bring you into full compliance without using a CNAME for the MX record
(which is a rfc MUST NOT).

Jim

--
EsisNet.com Webmail Client




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