tcptraceroute might give you more clues as to where it's going wrong. In
particular I'd look at local egress rules not allowing connections to
port 587 outside of the lan.
On Sun, 14 May 2023, Tom Reed wrote:
On Sun, May 14, 2023 at 08:36:38AM +0800, Tom Reed wrote:
tcp 0 0 0.0.0.0:587 0.0.0.0:*
LISTEN
32157/master
And the telnet results:
$ telnet 193.106.250.xx 587
Trying 193.106.250.xx...
telnet: Unable to connect to remote host: Connection timed out
So, it looks like it's not a LAN address. It's a mail server on the
public Internet? As in, your telnet client and your server are NOT
talking directly to each other over a straight ethernet connection?
There's routers and stuff in between them?
Yes. my mailserver is in NYC DC, and the client host is in Dallas DC.
You'd need to investigate the possibility of a firewall-equivalent at
each hop along the way.
I may need tcpdump for watching the rst packages.
Thank you
Tom
