Is Your Server/Firewall Properly Configured For Inbound SMTP from (TSB) TheSpamBusters.com ?
To expand our capacity, we have been in the process of directing additional traffic to servers with IP addresses that we first publicized a year ago.
If you have configured your firewall (or your customers' firewall) to accept inbound SMTP traffic only from our networks, please be sure that you have updated your firewall to include all of our IP addresses:
18.104.22.168 / 255.255.255.0 22.214.171.124 / 255.255.255.0 126.96.36.199 / 255.255.255.0 188.8.131.52 / 255.255.255.0 184.108.40.206 / 255.255.255.0 220.127.116.11 / 255.255.255.0 18.104.22.168 / 255.255.255.0 22.214.171.124 / 255.255.255.0 126.96.36.199 / 255.255.255.0 188.8.131.52 / 255.255.255.0 184.108.40.206 / 255.255.255.0
This only affects customers who have configured their firewall or mail server to only accept inbound SMTP traffic from our networks, and no changes are necessary for ports other than for SMTP port 25.
Thank you for your attention.