Email to Hotmail gets rejected
I have a Comcast Business service with static IPs. My Comcast modem is set to a bridge-like configuration, without any NAT (I have my own router/firewall). I also have my own mail server.
Yesterday, I started getting email rejected by Hotmail. I did not have problems in the past, and email sent to other locations is working (e.g., Gmail). This is part of the "Undelivered Mail Returned to Sender" message.
hotmail-com.olc.protection.outlook.com[220.127.116.11] said: 550 5.7.1Service unavailable, Client host [18.104.22.168] blocked using Spamhaus.To request removal from this list seehttps://www.spamhaus.org/query/ip/22.214.171.124 (AS3130).
126.96.36.199 is NOT my IP address. It also NOT my Comcast Gateway (which is 188.8.131.52).
184.108.40.206 is a Comcast machine, apparently in a block of dynamic IP addresses, as the address is blacklisted by Spamhaus.
Using MxToolbox Blacklist check, I find that:
- my IP addresses are not on ANY blacklists
- 220.127.116.11 is on two blacklists, including Spamhaus
Checking Spamhaus directly confirms the above.
I had a friend at a remote site (also on Comcast business) do a traceroute to the static IP address of my mail server. The last few lines of the trace are:
27 18.104.22.168 (22.214.171.124) 72.824 ms 72.788 ms 72.839 ms
28 126.96.36.199 (188.8.131.52) 80.586 ms 68.155 ms 68.081 ms
29 184.108.40.206 (220.127.116.11) 67.826 ms 67.870 ms 67.952 ms
30 c-73-125-101-117.hsd1.fl.comcast.net (18.104.22.168) 86.232 ms 86.194 ms 86.164 ms
Traceroute never gets back to my IP address. It stops at 22.214.171.124 - the address that Hotmail is complaining is blacklisted.
When I traceroute back to my friend's IP address (from my server), I don't see 126.96.36.199 in ANY of the hops. The first few lines:
1 _gateway (10.67.238.1) 0.222 ms 0.167 ms 0.257 ms
2 96-77-46-150-static.hfc.comcastbusiness.net (188.8.131.52) 2.356 ms 2.644 ms 4.297 ms
3 184.108.40.206 (220.127.116.11) 13.461 ms 21.359 ms 20.202 ms
4 18.104.22.168 (22.214.171.124) 23.654 ms 23.755 ms 24.012 ms
5 126.96.36.199 (188.8.131.52) 23.256 ms 23.227 ms 23.170 ms
6 184.108.40.206 (220.127.116.11) 19.961 ms 19.088 ms 19.396 ms
7 18.104.22.168 (22.214.171.124) 22.471 ms 20.491 ms 21.209 ms
8 be-33831-cs03.miami.fl.ibone.comcast.net (126.96.36.199) 21.884 ms be-33821-cs02.miami.fl.ibone.comcast.net (188.8.131.52) 15.875 ms 19.810 ms
In summary: traceroute from the outside to my static IP address stops at 184.108.40.206, but when I traceroute to an external IP address from my server, 220.127.116.11 is not in the route.
Is Hotmail blocking my emails because it is doing something similar to a traceroute back to my email server, which stops at 18.104.22.168 - an address that unfortunately is blacklisted by Spamhaus?
Why does traceroute to my static IP address from the outside stop at 22.214.171.124, and NOT my IP address?
How can this be fixed?