This is all within a LAN. My server can be pinged. I can run php apps on my server from within the LAN.

I have installed openssh-server. I tried the command:

ps aux

and it shows the:

process listed as /usr/sbin/sshd -D

However, when I try the command:

netstat -tulpn

the PID/Program name column is blank (I mean it has a hyphen).

Honestly, I don't understand this area too well.

But the strange thing is that SSH used to work but it suddenly stopped. I'd really love to have some help on resolving this.

EDIT:

I Just realised that I cannot even run php apps via a browser. But localhost in the URI works with the default index.html page.

MORE INFO:

Just for the record, I never changed any iptables settings. Only after I got stuck with this problem that I did iptables -F.

I've even tried reinstalling ssh a couple of times but I do get the feeling that the entries in iptables are causing this problem as I learnt from the comments of below.

If I turn off the firewall with ufw disable, ssh localhost works.

Now when I try accessing this server from another PC, I get a pretty big error message like this:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @   

WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS

POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be

eavesdropping on you right now (man-in-the-middle attack)! It is also

possible that a host key has just been changed. The fingerprint for

the ECDSA key sent by the remote host is

d4:........4:e9:75:06:61. Please contact your

system administrator. Add correct host key in

/home/khalid/.ssh/known_hosts to get rid of this message. Offending

ECDSA key in /home/khalid/.ssh/known_hosts:1   remove with: ssh-keygen

-f "/home/khalid/.ssh/known_hosts" -R 192.168.1.6 ECDSA host key for 192.168.X.X has changed and you have requested strict checking. Host key verification failed.

and there's no connection.