3CX SMTP server - Connection timed out

[Lukas Sukdol]

Hi, I am not able to get the SMTP server work after fresh debian install of 3CX community (free) version 15.5, location Europe, Czech republic. Still the same message, Connection time out: Ensure that Port 2528 TCP is open for outbound traffic. We have no restriction for outgoing traffic, no specific firewall on the line. Firewall check on Dashboard shows no problem (green check mark..) Any idea whats wrong?? Thanks a lot

 

[craigreilly]

This uses a 3rd party called SendGrid, atleast here in the US.
Ping this: smtp.3cx.net
Then see if you can Telnet to that address:2528

 

[Lukas Sukdol]

ping smtp.3cx.net
=> ping: cannot resolve smtp.3cx.net: Unknown host

 

[craigreilly]

you are right - me too.
sorry - try
smtp-proxy.3cx.net

 

[Lukas Sukdol]

its much better
but,
from my location (another ISP provider) I take this response:
64 bytes from 35.188.21.33: icmp_seq=0 ttl=54 time=169.686 ms
64 bytes from 35.188.21.33: icmp_seq=1 ttl=54 time=293.878 ms
...
and from 3cx installation location I receive this:
64 bytes from 116.171.188.35.bc.googleusercontent.com (35.188.171.116): icmp_seq=1 ttl=50 time=154 ms
64 bytes from 116.171.188.35.bc.googleusercontent.com (35.188.171.116): icmp_seq=2 ttl=50 time=150 ms

suddenly the response is ok (same from both locations) and from all 5 IP addresses
dig smtp-proxy.3cx.net =>
smtp-proxy.3cx.net. 2728 IN A 35.188.171.116
smtp-proxy.3cx.net. 2728 IN A 35.196.8.145
smtp-proxy.3cx.net. 2728 IN A 35.196.84.254
smtp-proxy.3cx.net. 2728 IN A 35.199.182.40
smtp-proxy.3cx.net. 2728 IN A 35.188.21.33

avg time ~150ms

I can not telnet this IPs:2528 - telnet needs whitespace instead of double dot.
telnet smtp-proxy.3cx.net 2528
connects me to the smtp server...