[ale] Need help reading tcpdump output

[Gary MacKay]

I have a cable modem and a DSL line in my office. I use the cable modem
to serve 'net access to my internal network and the DSL only has my
email/web server on it. I am having problems sending email to a few
domains, not all, just a few. I found I can telnet to port 25 of one of
the failing domains via my cable modem, but not via the DSL line. Below
are the first packett trace of each. The only thing I can see different
is the flags SWE instead of just S. I do not know enough about the flags
to know what that means nor how to fix it. The address I'm trying to
send email to is 170.206.225.44.

--------DSL Line: fails
19:32:35.162544 207.87.222.229.15255 > 170.206.225.44.25: SWE
3747157433:3747157433(0) win 5840 <mss 1460,sackOK,timestamp 303797345
0,nop,wscale 0> (DF) [tos 0x10]

--------Cable modem: works
15:39:37.774455 11.22.33.44.41159 > 170.206.225.44.25: S
3934758720:3934758720(0) win 5840 <mss 1460,sackOK,timestamp 329647437
0,nop,wscale 0> (DF) [tos 0x10]

Both lines have a firewall with the exact same firewall rules, except
for ports 25 and 110 on the DSL line. What am I missing?

- Gary

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