Cygwin sshd broken by seemingly trivial network change

[Andrey Repin]

Greetings, worsafe@bellsouth.net!

> While installing a new router, I changed my local network from 
> 192.168.4.* to 192.168.50.*. This seems to have broken Cygwin sshd on 
> both of my remote computers, but only for Cygwin; sshd works fine if I 
> boot the remote computer from a linux thumb drive. I have noticed no 
> other problems with the new network configuration.
> --------
> ssh -vvv does not give any messages that look useful to me. 
> Authentication problems usually give some useful message, but this seems 
> to fail before getting that far:

> ssh -vvv $ASUS12
> OpenSSH_8.3p1, OpenSSL 1.1.1f 31 Mar 2020
> debug1: Reading configuration data /home/cdr/.ssh/config
> debug1: /home/cdr/.ssh/config line 1: Applying options for *
> debug1: Reading configuration data /etc/ssh_config
> debug2: resolve_canonicalize: hostname 192.168.50.105 is address
> debug2: ssh_connect_direct
> debug1: Connecting to 192.168.50.105 [192.168.50.105] port 22.
> debug1: connect to address 192.168.50.105 port 22: Connection timed out
> ssh: connect to host 192.168.50.105 port 22: Connection timed out
> -----------
> The server is running, as confirmed by cyrunsrv -Q sshd.
> /var/log/sshd.log is an empty file.
> -------
> nmap shows port 22 open on the remote server:
> nmap -p22 $ASUS12
> Nmap scan report for asus12 (192.168.50.105)
> Host is up (0.13s latency).
> PORT STATE SERVICE
> 22/tcp filtered ssh
> ----------
> However, telnet fails before returning the expected header string:
> telnet $ASUS12 22
> Connecting To 192.168.50.105...Could not open connection to the host, on 
> port 22
> : Connect failed
> (For comparison, linux returns the string "SSH-2.0-OpenSSH_7.9p1 
> Debian-10+deb10u2")
> -------
> I can't think what to try short of reinstalling sshd.

Re-cehck the windows firewall settings.
Manually open port 22 for incoming connections regardless of the app it is
using or any addresses.


-- 
With best regards,
Andrey Repin
Friday, December 18, 2020 11:28:10

Sorry for my terrible english...