Although TCP wrappers were fine unfortunately IPtables wasn't.
Thanks for your help, it made a difference.
Another reason is:
it could be a bad generated tcp/ip packet, so that could be a reason from
the lack of ip header, or a IPV6 packet, or even another type of packet
(UDP, PPPoE, PPPTP, Tunnel).
did you change any library ?
any attack on your system ?
You can check by:
1)from local computer execute "ssh 127.0.0.1
what happens? if you get an error message
try to check /etc/ssh/sshd_config, perhaps something is wrong
if every thing is ok, try to reinstall sshd or update it
if you are using Redhat family ike fedora/centos...
execute "rpm -V sshd" and see result
2)from remote host execute "ssh ......."
what happens(check with different client)
also see /var/log/messages /var/log/secure
3) what about firewall or iptables ?
execute "iptables -L" and see result
Check service sshd on your server is run or not
after view is port is open or not
afte ssh to local-server and read /var/log/secure and /var/log/messages
Can you connect to ssh from the ssh server itself using 127.0.0.1 and then by its IP address?