Centos – SSH works locally but not remotely

Recently ran into a hardware issue on my CentOS machine. After a PSU, ram, mobo and CPU replacement I think I have the hardware issue resolved.

However, I believe I have a network configuration issue causing SSH remote connection failures.

I tried regular ssh using my original account and key and I receive a connection timeout after server is expecting: debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP.

From the server itself with a new account:

$ ssh -v -o PubkeyAuthentication=no chris@localhost
Last login: ... 
[chris@dev ~]$ 

From a remote connection on the LAN to try remote SSH:

chris::Internets|10 ~ $ ssh -v -o PubkeyAuthentication=no chris@pug
OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011
debug1: Reading configuration data /Users/chris/.ssh/config
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: /etc/ssh_config line 102: Applying options for *
debug1: Connecting to pug [192.168.1.175] port 22.
debug1: Connection established.
debug1: identity file /Users/chris/.ssh/id_rsa type 1
debug1: identity file /Users/chris/.ssh/id_rsa-cert type -1
debug1: identity file /Users/chris/.ssh/id_dsa type -1
debug1: identity file /Users/chris/.ssh/id_dsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH_5*
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
Read from socket failed: Operation timed out

I have verified I can:

• ping remote boxes on lan and internet from server
• cannot wget web pages from server
• ping server from lan
• can access ssh port from lan or remote connection (still receive ssh errors)

I did see a post regarding DNS resolution issues causing an issue, I have UseDNS No which should avoid DNS entirely and not cause issues.

Any ideas here as I am scratching my head for what else to look for?

Edit:

/var/log/secure has the following contents:

Nov 29 11:19:45 dev sshd[5978]: fatal: Read from socket failed: Connection reset by peer

Also, I checked and SSH is listening on 22 as it should be.

[root@dev ~]# lsof -i TCP:22 | grep LISTEN 
sshd 5424 root 3u IPv4 39030 0t0 TCP *:ssh (LISTEN)
sshd 5424 root 3u IPv6 39032 0t0 TCP *:ssh (LISTEN)

To avoid complications, I flushed iptables:

[root@dev ~]# iptables -L -n 
Chain INPUT (policy ACCEPT)
target prot opt source destination 

Chain FORWARD (policy ACCEPT)
target prot opt source destination 

Chain OUTPUT (policy ACCEPT)
target prot opt source destination