Server is failing SSH connections

Not certain what's happened here, but any SSH connection to my server is failing. Yesterday it was working, today it is not. - **Server**: Centos 6.10 cPanel v86.0.18 - **Client**: Windows systems using Putty SSH I am on a Windows machine using Putty. I can connect to the IP on port 22. If I type the wrong password, it gives me the password prompt again. If I provide the correct password it either just closes the session window or gives me an error Server unexpectedly closed network connection. On my local firewall, the logs are showing the session ended due to a tcp-fin packet - meaning the remote server closed the session. From within cPanel I use the Terminal app to emulate a console session and I am able to get root command line: [root@sX-X-X-X ~]#. From there I then ssh to itself: ssh username@x.x.x.x - and I get this error: dup() in/out/err failed I restarted the sshd and the problem persists. What can I do or look at to get this resolved? ### Update 1 Ran this debug command from prompt: [root@X.X.X.X ~]# ssh -vvvo PreferredAuthentications=password userID@X.X.X.X OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug2: ssh_connect: needpriv 0 debug1: Connecting to X.X.X.X [X.X.X.X] port 22. debug1: Connection established. debug1: permanently_set_uid: 0/0 debug1: identity file /root/.ssh/identity type -1 debug1: identity file /root/.ssh/identity-cert type -1 debug1: identity file /root/.ssh/id_rsa type -1 debug1: identity file /root/.ssh/id_rsa-cert type -1 debug1: identity file /root/.ssh/id_dsa type -1 debug1: identity file /root/.ssh/id_dsa-cert type -1 debug1: identity file /root/.ssh/id_ecdsa type -1 debug1: identity file /root/.ssh/id_ecdsa-cert type -1 debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3 debug1: match: OpenSSH_5.3 pat OpenSSH* debug1: Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_5.3 debug2: fd 3 setting O_NONBLOCK debug1: SSH2_MSG_KEXINIT sent debug3: Wrote 864 bytes for a total of 885 debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se debug2: kex_parse_kexinit: hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96 debug2: kex_parse_kexinit: hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96 debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib debug2: kex_parse_kexinit: none,zlib@openssh.com,zlib debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se debug2: kex_parse_kexinit: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,aes256-cbc,arcfour,rijndael-cbc@lysator.liu.se debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,umac-64@openssh.com,hmac-sha2-256,hmac-sha2-512,hmac-ripemd160,hmac-ripemd160@openssh.com,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib@openssh.com debug2: kex_parse_kexinit: none,zlib@openssh.com debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_setup: found hmac-sha1 debug1: kex: server->client aes128-ctr hmac-sha1 none debug2: mac_setup: found hmac-sha1 debug1: kex: client->server aes128-ctr hmac-sha1 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<2048<8192) sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug3: Wrote 24 bytes for a total of 909 debug2: dh_gen_key: priv key bits set: 161/320 debug2: bits set: 1000/2048 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug3: Wrote 272 bytes for a total of 1181 debug3: check_host_in_hostfile: host 166.62.85.95 filename /root/.ssh/known_hosts debug3: check_host_in_hostfile: host 166.62.85.95 filename /root/.ssh/known_hosts debug3: check_host_in_hostfile: match line 1 debug1: Host 'X.X.X.X' is known and matches the RSA host key. debug1: Found key in /root/.ssh/known_hosts:1 debug2: bits set: 1030/2048 debug1: ssh_rsa_verify: signature correct debug2: kex_derive_keys debug2: set_newkeys: mode 1 debug1: SSH2_MSG_NEWKEYS sent debug1: expecting SSH2_MSG_NEWKEYS debug3: Wrote 16 bytes for a total of 1197 debug2: set_newkeys: mode 0 debug1: SSH2_MSG_NEWKEYS received debug1: SSH2_MSG_SERVICE_REQUEST sent debug3: Wrote 52 bytes for a total of 1249 debug2: service_accept: ssh-userauth debug1: SSH2_MSG_SERVICE_ACCEPT received debug2: key: /root/.ssh/identity ((nil)) debug2: key: /root/.ssh/id_rsa ((nil)) debug2: key: /root/.ssh/id_dsa ((nil)) debug2: key: /root/.ssh/id_ecdsa ((nil)) debug3: Wrote 84 bytes for a total of 1333 debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password debug3: start over, passed a different list publickey,gssapi-keyex,gssapi-with-mic,password debug3: preferred password debug3: authmethod_lookup password debug3: remaining preferred: debug3: authmethod_is_enabled password debug1: Next authentication method: password userID@X.X.X.X's password: debug3: packet_send2: adding 48 (len 72 padlen 8 extra_pad 64) debug2: we sent a password packet, wait for reply debug3: Wrote 148 bytes for a total of 1481 Segmentation fault ### Update 2 I have tried ssh via several different user accounts, even root -- I get the same results for all users. Here is the user output info: $ grep userID /etc/passwd $ userID:x:501:501::/home/userID:/bin/bash $ ls -1 /proc/1121/fd | wc -l 4 $ cat /proc/sys/fs/file-max 262144 $ cat /proc/sys/fs/file-nr 139584 0 262144 $ df -h Filesystem Size Used Avail Use% Mounted on /dev/ploop34902p1 118G 14G 100G 12% / none 2.0G 4.0K 2.0G 1% /dev none 2.0G 0 2.0G 0% /dev/shm Also reboot did nothing, still unable to ssh. ### Update 3 From my SSH logs, its accepting the password and then immediately closing the session: Apr 21 11:44:09 sX.X.X.X sshd: Accepted password for myAdminID from 47.200.121.187 port 4283 ssh2 Apr 21 11:44:09 sX.X.X.X sshd: pam_unix(sshd:session): session opened for user myAdminID by (uid=0) Apr 21 11:44:10 sX.X.X.X sshd: pam_unix(sshd:session): session closed for user myAdminID