Intermittent disconnects



Recently, I have noticed that while connected to my system via SSH, I
will suddenly get disconnected. It does not seem to matter if it is
idle or I am in the middle of typing. I recall that in the past, I
would be able to keep a "top" window up for days.

OS: RHEL5.4
Server: OpenSSH 4.3p2-65
Client: Putty 0.60

I was able to capture the part of the log where this occurred:

Dec 15 17:26:42 host_name sshd[3568]: Received signal 15; terminating.
Dec 15 17:26:42 host_name sshd[18331]: debug1: Bind to port 22 on ::.
Dec 15 17:26:42 host_name sshd[18331]: Server listening on :: port 22.
Dec 15 17:26:42 host_name sshd[18331]: debug1: Bind to port 22 on
0.0.0.0.
Dec 15 17:26:42 host_name sshd[18331]: error: Bind to port 22 on
0.0.0.0 failed: Address already in use.
Dec 15 17:27:07 host_name sshd[18404]: debug1: rexec start in 4 out 4
newsock 4 pipe 6 sock 7
Dec 15 17:27:07 host_name sshd[18331]: debug1: Forked child 18404.
Dec 15 17:27:07 host_name sshd[18404]: debug1: inetd sockets after
dupping: 3, 3
Dec 15 17:27:07 host_name sshd[18404]: Connection from xxx.xxx.xxx.xxx
port 3919
Dec 15 17:27:07 host_name sshd[18404]: debug1: Client protocol version
2.0; client software version PuTTY_Release_0.60
Dec 15 17:27:07 host_name sshd[18404]: debug1: no match:
PuTTY_Release_0.60
Dec 15 17:27:07 host_name sshd[18404]: debug1: Enabling compatibility
mode for protocol 2.0
Dec 15 17:27:07 host_name sshd[18404]: debug1: Local version string
SSH-2.0-OpenSSH_4.3
Dec 15 17:27:07 host_name sshd[18405]: debug1: permanently_set_uid:
74/74
Dec 15 17:27:07 host_name sshd[18405]: debug1: list_hostkey_types: ssh-
rsa,ssh-dss
Dec 15 17:27:07 host_name sshd[18405]: debug1: SSH2_MSG_KEXINIT sent
Dec 15 17:27:07 host_name sshd[18405]: debug1: SSH2_MSG_KEXINIT
received
Dec 15 17:27:07 host_name sshd[18405]: debug1: kex: client->server
aes256-ctr hmac-sha1 none
Dec 15 17:27:07 host_name sshd[18405]: debug1: kex: server->client
aes256-ctr hmac-sha1 none
Dec 15 17:27:07 host_name sshd[18405]: debug1:
SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received
Dec 15 17:27:07 host_name sshd[18405]: debug1:
SSH2_MSG_KEX_DH_GEX_GROUP sent
Dec 15 17:27:07 host_name sshd[18405]: debug1: expecting
SSH2_MSG_KEX_DH_GEX_INIT
Dec 15 17:27:07 host_name sshd[18405]: debug1:
SSH2_MSG_KEX_DH_GEX_REPLY sent
Dec 15 17:27:07 host_name sshd[18405]: debug1: SSH2_MSG_NEWKEYS sent
Dec 15 17:27:07 host_name sshd[18405]: debug1: expecting
SSH2_MSG_NEWKEYS
Dec 15 17:27:07 host_name sshd[18405]: debug1: SSH2_MSG_NEWKEYS
received
Dec 15 17:27:07 host_name sshd[18405]: debug1: KEX done
Dec 15 17:27:29 host_name sshd[18405]: debug1: userauth-request for
user enricong service ssh-connection method none
Dec 15 17:27:29 host_name sshd[18405]: debug1: attempt 0 failures 0
Dec 15 17:27:29 host_name sshd[18404]: debug1: PAM: initializing for
"enricong"
Dec 15 17:27:29 host_name sshd[18404]: debug1: PAM: setting PAM_RHOST
to "hostname.com"
Dec 15 17:27:29 host_name sshd[18404]: debug1: PAM: setting PAM_TTY to
"ssh"
Dec 15 17:27:35 host_name sshd[18405]: debug1: userauth-request for
user enricong service ssh-connection method password
Dec 15 17:27:35 host_name sshd[18405]: debug1: attempt 1 failures 1
Dec 15 17:27:35 host_name sshd[18404]: debug1: PAM: password
authentication accepted for enricong
Dec 15 17:27:35 host_name sshd[18404]: debug1: do_pam_account: called
Dec 15 17:27:35 host_name sshd[18404]: Accepted password for enricong
from xxx.xxx.xxx.xxx port 3919 ssh2
Dec 15 17:27:35 host_name sshd[18404]: debug1: monitor_child_preauth:
enricong has been authenticated by privileged process
Dec 15 17:27:35 host_name sshd[18404]: debug1: temporarily_use_uid:
500/500 (e=0/0)
Dec 15 17:27:35 host_name sshd[18404]: debug1: ssh_gssapi_storecreds:
Not a GSSAPI mechanism
Dec 15 17:27:35 host_name sshd[18404]: debug1: restore_uid: 0/0
Dec 15 17:27:35 host_name sshd[18404]: debug1: PAM: establishing
credentials
Dec 15 17:27:35 host_name sshd[18404]: pam_unix(sshd:session): session
opened for user enricong by (uid=0)
Dec 15 17:27:35 host_name sshd[18455]: debug1: PAM: reinitializing
credentials
Dec 15 17:27:35 host_name sshd[18455]: debug1: permanently_set_uid:
500/500
Dec 15 17:27:35 host_name sshd[18455]: debug1: Entering interactive
session for SSH2.
Dec 15 17:27:35 host_name sshd[18455]: debug1: server_init_dispatch_20
Dec 15 17:27:35 host_name sshd[18455]: debug1:
server_input_channel_open: ctype session rchan 256 win 16384 max 16384
Dec 15 17:27:35 host_name sshd[18455]: debug1: input_session_request
Dec 15 17:27:35 host_name sshd[18455]: debug1: channel 0: new [server-
session]
Dec 15 17:27:35 host_name sshd[18455]: debug1: session_new: init
Dec 15 17:27:35 host_name sshd[18455]: debug1: session_new: session 0
Dec 15 17:27:35 host_name sshd[18455]: debug1: session_open: channel 0
Dec 15 17:27:35 host_name sshd[18455]: debug1: session_open: session
0: link with channel 0
Dec 15 17:27:35 host_name sshd[18455]: debug1:
server_input_channel_open: confirm session
Dec 15 17:27:35 host_name sshd[18455]: debug1:
server_input_channel_req: channel 0 request x11-req reply 1
Dec 15 17:27:35 host_name sshd[18455]: debug1: session_by_channel:
session 0 channel 0
Dec 15 17:27:35 host_name sshd[18455]: debug1:
session_input_channel_req: session 0 req x11-req
Dec 15 17:27:35 host_name sshd[18455]: debug1: channel 1: new [X11
inet listener]
Dec 15 17:27:35 host_name sshd[18455]: debug1: channel 2: new [X11
inet listener]
Dec 15 17:27:35 host_name sshd[18455]: debug1:
server_input_channel_req: channel 0 request pty-req reply 1
Dec 15 17:27:35 host_name sshd[18455]: debug1: session_by_channel:
session 0 channel 0
Dec 15 17:27:35 host_name sshd[18455]: debug1:
session_input_channel_req: session 0 req pty-req
Dec 15 17:27:35 host_name sshd[18455]: debug1: Allocating pty.
Dec 15 17:27:35 host_name sshd[18404]: debug1: session_new: init
Dec 15 17:27:35 host_name sshd[18404]: debug1: session_new: session 0
Dec 15 17:27:35 host_name sshd[18404]: debug1: user_context:
user_u:system_r:unconfined_t old_tty_context: user_u:object_r:devpts_t
Dec 15 17:27:35 host_name sshd[18455]: debug1: session_pty_req:
session 0 alloc /dev/pts/8
Dec 15 17:27:35 host_name sshd[18455]: debug1:
server_input_channel_req: channel 0 request shell reply 1
Dec 15 17:27:35 host_name sshd[18455]: debug1: session_by_channel:
session 0 channel 0
Dec 15 17:27:35 host_name sshd[18455]: debug1:
session_input_channel_req: session 0 req shell
Dec 15 17:27:35 host_name sshd[18456]: debug1: Setting controlling tty
using TIOCSCTTY.
Dec 15 17:27:36 host_name sshd[18455]: debug1: Received SIGCHLD.
Dec 15 17:27:36 host_name sshd[18455]: debug1: session_by_pid: pid
18456
Dec 15 17:27:36 host_name sshd[18455]: debug1: session_exit_message:
session 0 channel 0 pid 18456
Dec 15 17:27:36 host_name sshd[18455]: debug1: session_exit_message:
release channel 0
Dec 15 17:27:36 host_name sshd[18404]: debug1: session_by_tty: session
0 tty /dev/pts/8
Dec 15 17:27:36 host_name sshd[18404]: debug1: session_pty_cleanup:
session 0 release /dev/pts/8
Dec 15 17:27:36 host_name sshd[18455]: debug1: session_by_channel:
session 0 channel 0
Dec 15 17:27:36 host_name sshd[18455]: debug1:
session_close_by_channel: channel 0 child 0
Dec 15 17:27:36 host_name sshd[18455]: debug1: session_close_x11:
detach x11 channel 1
Dec 15 17:27:36 host_name sshd[18455]: debug1: session_close_x11:
detach x11 channel 2
Dec 15 17:27:36 host_name sshd[18455]: debug1: session_close: session
0 pid 0
Dec 15 17:27:36 host_name sshd[18455]: debug1: channel 0: free: server-
session, nchannels 3
Dec 15 17:27:36 host_name sshd[18455]: debug1: channel 1: free: X11
inet listener, nchannels 2
Dec 15 17:27:36 host_name sshd[18455]: debug1: channel 2: free: X11
inet listener, nchannels 1
Dec 15 17:27:36 host_name sshd[18455]: Connection closed by
xxx.xxx.xxx.xxx
Dec 15 17:27:36 host_name sshd[18455]: debug1: do_cleanup
Dec 15 17:27:36 host_name sshd[18455]: Closing connection to
xxx.xxx.xxx.xxx
Dec 15 17:27:36 host_name sshd[18404]: debug1: PAM: cleanup
Dec 15 17:27:36 host_name sshd[18404]: debug1: PAM: deleting
credentials
Dec 15 17:27:36 host_name sshd[18404]: debug1: PAM: closing session
Dec 15 17:27:36 host_name sshd[18404]: pam_unix(sshd:session): session
closed for user enricong
Dec 15 17:56:56 host_name sshd[14767]: fatal: monitor_read:
unsupported request: 2
Dec 15 17:56:56 host_name sshd[14767]: pam_unix(sshd:session): session
closed for user enricong
Dec 15 17:56:56 host_name su: pam_unix(su-l:session): session closed
for user root
Dec 15 18:04:58 host_name su: pam_unix(su:session): session closed for
user root

.



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