Having received a call from a customer today having problems receiving mail from their customers via our Mail Servers, I looked through our Anti-Spam logs (Vamsoft ORF) and filtered the logs to show rejected mail for them and then I looked through the rejected mail for the problem sender and checked out the details of the sending server, which turned out to have the following Fully Qualified Domain Name:
The related IP Address was 22.214.171.124 which is a BT IP Address. I then re-filtered the logs to show all mail from servers with an FQDN of *.HE.LOCAL and there were about 60 entries all coming from similar named servers:
Well – all the related IP Addresses are BT IP Addresses and half of the sender addresses were *@BTCONNECT.COM addresses, which would suggest to me that they are all BT Mail Servers.
So – what’s the problem? Well, the problem is that any mail server that is configured with an FQDN ending .LOCAL is not RFC Compliant (email standards) because the FQDN must resolve back to the IP Address that the server is connected to the internet with but a .LOCAL FQDN cannot be resolved as .LOCAL domain names are only resolvable internally and thus when a receiving server sees a .LOCAL FQDN, then server may reject the connection attempt because it cannot resolve the FQDN in DNS and thinks the server is a spamming server.
So – BT need to get their act together and configure their servers properly as their customer’s emails will be getting rejected by some other mail servers (including ours) and as usual, the people sending the emails will think that it is a problem with the receiving server, which it isn’t.