scp times out

[Josef Lowder]

Matt Graham wrote:
> First thing I'd check is the iptables rulesets. An overly paranoid
> firewall could cause this to happen. Second thing I'd check is the
> /etc/ssh/sshd_config , to make sure that sshd is listening on that
> interface (or all interfaces) and port 22. "pgrep sshd" returns a
> PID, right? If it doesn't, there's your problem right there.

How does one "check the iptables rulesets"?
How does one deetermine if "sshd is listening"?

pgrep sshd  gives no response.
so what does that mean?  and how can I fix that?

This scp worked a year ago when I tried it and I've made
no changes in this system since ... so what's next?