Michael Monnerie wrote: > On Mittwoch, 26. April 2006 16:09 Pablo Allietti wrote: >> i need to chage for example NO_RDNS rule to >> give 3.0 > > Don't do that, it's not required for a mail server to have an RDNS. At > least, it used to be the last time I looked into the RFCs. Technically, it's not required, but the RFCs do recommend that *ALL* IP addresses to have a PTR record if they are in-use on the internet.
That said, you pretty much have to do this for your outbound mailservers because several LARGE ISPs will not accept mail from hosts with no RDNS. This includes AOL and Comcast off the top of my head. If you want to be able to email users at those sites, you need RDNS. I think you can count on most MXes dropping connections from hosts with no RDNS in a few years. As this practice becomes more common, there will be fewer "legitimate" sites that are mis-administered in this way. As time goes on and there are fewer misconfigured sites it will become more popular to block them because there will be fewer legitimate mails blocked.
