On Ubuntu 20.04, unable to ssh to server, after upgrade from 18.04

Shaik Musthafa

3/28/24, 12:35 PM

After upgrading ubuntu from 18.04 to 20.04, unable to connect to host with my user

Below are the logs from auth.log

Mar 28 12:27:13 tpvm sshd[1590]: debug1: userauth-request for user XXXXX service ssh-connection method password [preauth]
Mar 28 12:27:13 tpvm sshd[1590]: debug1: attempt 2 failures 1 [preauth]
Mar 28 12:27:13 tpvm sshd[1590]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=x.y.z.r  user=XXXXX
Mar 28 12:27:13 tpvm sshd[1590]: pam_ldap: could not open secret file /etc/ldap.secret (No such file or directory)
Mar 28 12:27:13 tpvm sshd[1590]: pam_ldap: ldap_search_s No such object
Mar 28 12:27:15 tpvm sshd[1590]: debug1: PAM: password authentication failed for XXXXX: Authentication failure
Mar 28 12:27:15 tpvm sshd[1590]: Failed password for XXXXX from x.y.z.r port 54880 ssh2

I had a VM with 18.04 running, with a specific user XXXXX. Password is set to the User(XXXXX). After upgrading to 20.04 LTS, I am unable to perform ssh to VM with XXXXX user and password. But after upgrade to 20.04, if I remove already configured password and re configure it again then ssh to VM with XXXXX user and password is working fine

355

0 + 8

ssh

authentication

pam

pam-environment

20.04

Rishon JR

3/28/24, 12:39 PM

Try `sudo apt reinstall openssh-server`

Rishon JR

3/28/24, 12:42 PM

You can also follow this [article](https://kb.iu.edu/d/aews).

steeldriver

3/28/24, 12:54 PM

This looks like a problem with either your PAM configuration or /etc/nsswitch.conf - are you intentionally using LDAP authentication or are you expecting it to use pam_unix?

warren

3/28/24, 1:19 PM

is your secondary sshd instance still running?

Shaik Musthafa

3/29/24, 6:23 AM

HI @steeldriver, I am expecting it to use pam_unix. Can you pls provide me the correct PAM configuration and /etc/nsswitch.conf

Shaik Musthafa

3/29/24, 6:25 AM

HI @warren, no ps -ef | grep sshd root 848 1 0 06:21 ? 00:00:00 sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups root 1048 848 0 06:22 ? 00:00:00 sshd: XXXXX [priv] XXXXX 1171 1048 0 06:22 ? 00:00:00 sshd: XXXXX@pts/0 root 1221 1213 0 06:24 pts/0 00:00:00 grep --color=auto sshd

Shaik Musthafa

3/29/24, 6:56 AM

steeldriver

3/29/24, 12:46 PM

@ShaikMusthafa please use the [edit] button to add this new information to your question

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EN: On Ubuntu 20.04, unable to ssh to server, after upgrade from 18.04

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