Cygwin sshd broken by seemingly trivial network change

[Charles Russell]

SOLVED

On 12/17/2020 3:24 PM, Erik Soderquist wrote:

 > in some cases I could not find any real
 > issue, but deleting and recreating the rules fixed the issue.

That did the trick: simply deleting and reinstating the firewall 
settings for sshd solved the problem on both computers.

I had trouble deleting them initially, but this worked:

Select control panel; windows firewall; advanced settings
(If you have done something else under windows firewall before selecting 
advanced settings, you may not be asked for an administrative password. 
In that case, go back to control panel and start over.) Now select sshd, 
and in the right hand "actions" panel will appear an option to delete it.

After deletion, go back to Allow a Program through Windows Firewall, 
then reinstall it. (Windows would not let me do this until after 
rebooting, which I found out the hard way. Instead of a message, it 
would just beep with each letter while I entered the administrative 
password, and then reject the password. One of the nicest things about 
Cygwin is keeping Windows at arm's length.)

These steps fixed the problem on both computers. Why the minor network 
change precipitated the problem remains a mystery.