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Problem with SMTPS

0

tcpport465

The Bat! can get mail throught IMAP, but can't send messages.

Using secure smtp.yandex.ru

port is working.

asked 08 Aug '15, 16:30

Andrei%20S's gravatar image

Andrei S
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accept rate: 0%

From the looks of it: the TCP port is not working.

(08 Aug '15, 22:53) Jaap ♦

One Answer:

0

There is no SYN-ACK for the SYN.

As the server does answer to SYN on port 465, I see the following possible reasons for your problem:

  • your gateway (firewall) blocks TCP port 465
  • your gateway (firewall) does not do source NAT for that traffic
  • there is a problem with routing on your gateway (firewall), meaning the gateway does not know how to route traffic to smtp.yandex.ru. Maybe there is a network and/or host route to 213.180.204.xx on your gateway for whatever reason
  • somebody (your ISP) on the way between your gateway and the receiver blocks the SYN on port 465
  • the receiver side blocks the SYN from your client, maybe due to bad IP reputation or due to TCP flags/options in the SYN frame that it does not like

Regards
Kurt

answered 11 Aug '15, 16:17

Kurt%20Knochner's gravatar image

Kurt Knochner ♦
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accept rate: 15%