I currently have several servers at OVH including one that acts as a personal mail server. Postfix takes care of receiving the mails, but I have a problem for the reception coming from certain domains. After investigation I noticed that often the domains in question were hosted on the amazon network.
- Impossible to receive mails from amazon, adobe (54.240.14.29, 54.240.14.30 => amazon), pinterest (some mails also amazon).
- No problem to receive emails from gmail, outlook, mail.com, protonmail, between my personal domains.
- No iptables rules specific to ip.
- Postfix does not react at all to these connections with a smtpd -v in master.cf.
- tcpdump port 25 -s 0 -i any gives me as output:
00: 02: 41.274707 IP a27-171.smtp-out.us-west-2.amazonses.com.43934> srv.xxxxx.xxx.smtp: Flags [S], seq 1358324291, win 26883, options [mss 8961, sackOK, TS 55510897 ecr 0, nop, wscale 7], length 0
00: 02: 43.290697 IP a27-171.smtp-out.us-west-2.amazonses.com.43934> srv.xxxxx.xxx.smtp: Flags [S], seq 1358324291, win 26883, options [mss 8961, sackOK, TS 55512913 ecr 0, nop, wscale 7], length 0
00: 02: 47.450683 IP a27-171.smtp-out.us-west-2.amazonses.com.43934> srv.xxxxx.xxx.smtp: Flags [S], seq 1358324291, win 26883, options [mss 8961, sackOK, TS 55517073 ecr 0, nop, wscale 7], length 0
and then nothing.
Does anyone have such a concern and if so how did it settle?
Thanking you for your attention!
