Jump to content

user ssh login troubleshooting issues


rev.dennis
 Share

Recommended Posts

Here I am going to keep updating ways to troubleshoot ssh login issues on linux or unix operating systems.  Even though there are several different flavors and types of linux, the basis is typically the same.  I am currently running/testing these commands on a RH 5.x system


 


SSH Login Records


$ cat /var/log/secure


 


SSH Login Attempts


$ cat /var/log/auth.log


(some helpful filters)


$ grep sshd.*Failed /var/log/auth.log | less


$ grep sshd.*Did /var/log/auth.log | less


 


.ssh/authorized_keys


permissions, compare files checksum


 


Failed Login Attempts


$ grep "authentication failure" /var/log/secure | awk '{ print $13 }' | cut -b7-  | sort | uniq -c


 


Capture login attempts


$ tcpdump -w xpackets.pcap src 138.35.28.202 and port 22


NOTES:


$ tcpdump -D (shows available interfaces in the event you want to capture only on one interface with -i eth0)


$ tcpdump -r xpackets.pcap (will read the file file you just captured)


Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...