Multiple reverse DNS entries
I am hosting 4 domains on one linode and this domain are using web and email services.
Can we make some setting in DNS such that reverse DNS lookup is done for multiple domain names?
Current Sceneario:
hostname: mail.mydomain.com
Virtual domain: newdomain.com
When I send email to some other server using newdomain.com, the client SMTP server checks the rdns entry and linode returns mail.mydomain.com, so the email is marked as spam.
I have added DKIM and SPF entries for all domains … but still
Is there any way?
Richard
3 Replies
Im afraid reverse entries to my knowledge are 1 to 1 on the ip address.
That said, i host about 15 domains on my one linode, and all my mail comes from mail.our-lan.com and ive never had issues with the other mail hosts accepting it.
As long as you have the outgoing ip forward and reverse going the same way, and the mail server identifying itself as the right name, you should be fine..
@Internat:
Im afraid reverse entries to my knowledge are 1 to 1 on the ip address.
Theoretically you can have multiple rDNS entries for an IP address. But it's a bad bad bad idea; a common assumption is that the PTR lookup only returns one address and software may break if it returns more than one. I've no idea if the linode manager allows it, but don't do it even if you can
But, in practice, this isn't a restriction to worry about.
> As long as you have the outgoing ip forward and reverse going the same way, and the mail server identifying itself as the right name, you should be fine..
Yup! This is how it should work.
However, I can't see any situation where one would want that.
I very much doubt that the mail is classed as spam based on you not having PTR records that match any random domain that you are handling mail for. No one in their right mind would implement such a check.
As has been noted, the check that some do implement and that at least makes some sense is that the name that the SMTP server refers to itself as (nothing to do with the mail addresses) is the same as the PTR. (Which shouldn't mean any special configuration as the PTR is supposed to the the canonical name of the server anyway).