I run a VPS on a Windows Server 2008 machine, and since I got it in January 2015 everything has been running fine, the server has IIS, DNS, and uses Mailenable for email exchange.

I've been running multiple sites on it with absolutley no problems, until this past weekend, exactly 4 months after the server went live (I don't know if the 4 months is coincidence, but I thought its best to mention it anyway) I noticed I was getting Mail Delivery Errors in my inbox, and after investigating I saw I was getting this error in the SMTP logs:

Communications Error: Socket connection to gmail-smtp-in.l.google.com failed (error 10060). The host was either not contactable or it rejected your connection.

Because of this I am unable to send any email to an external server, at first I thought it was a problem with the software, Mailenable, but after a lot of research and digging about online, I found out I was still able to send a message from one domain hosted on the server, to another domain on the server, with no problems at all.

After even more digging I found out that you need to have a Reverse DNS PTR record, or your emails could get refused as spam, when I first set up the DNS back in January, I never created a Reverse DNS Zone, this was the first time I've had to configure my own server, so I didn't know the importance of a Reverse DNS Zone, so I never created one.

So on Sunday I created one, using instructions I found online, and as far as I can see, it looks as it should, but when I do a Reverse DNS look up online it still says the look up failed.

My server IP is, and I have an A record configured for mail.mydomain.com and an MX record configured also for mail.mydomain.com, and like I said, these have been fine for the last 4 months.

The Reverse DNS is set up as 23.33.178.in-addr.arpa and the PTR record is set up as:

FQDN: Host Name: mail.mydomain.com.

I can't see anything wrong with it, but my emails are still getting rejected from external hosts... I've been trying to fix this myself now for 4 days, with no luck, and I'm starting to get desperate...

So any help or ideas any has got will be greatly recieved.

Sorry for the lengthy post!

Thanks in advance, Jamie Peters


Your DNS server isn't authoritative for the ip address that your server is using, your ISP is authoritative for the ip address. You need your ISP to create the PTR record for your server in their Reverse Lookup zone.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.