Euro Fast Host

Does you client or customer call you to say they have a bounce saying your email server has rejected their email?

It might have Sending address not accepted due to spam filter and if you or someone has access to email logs it will show why it was rejected.

A common reason is Reverse DNS lookup or lack of it. This is fast becoming a standard feature to email Servers as it helps cut SPAM down hugely. In the logs it will show Mail rejected due to SMTP Spam Blocking: _REVERSEDNSLOOKUP and is usually because the company is using a mail exchange server from their office with no reverse DNS Lookup
The rejected email could cost you and them money so it does need fixing on the offending side and not implementing it is costing you money.

Reverse DNS or rDNS works in the opposite manner to the standard DNS in that it takes an IP address and resolves this to your domain name. Reverse DNS lookups was brought in a few years back now as a good way to combat spam for big ISP’s. Email spammers quite often used an IP address that does not correctly resolve to their host name. BT, AOL, Verizon, Yahoo and a lot of others will not receive email from a server that fails a Reverse DNS lookup. You should see these failed email attempts as bounce backs in your inbox.

I hope you see now why this is an important setting to have on a mail server.
How do you get reverse DNS working for your own servers in your office? The short answer is to contact your ISP and do one of the following:

1. Ask them to add a reverse DNS record for your domain to their DNS server.

Or:

2. Ask them to delegate authority for your reverse DNS to your own DNS servers (hoping you know how to do this).

Your ISP should be familiar with these types of requests and Option 1 will be enough.

Happy pain free emailing.