I have seen more than one question like this one and I think it's because the causes are many. So I would like to do a detailed question here to see if someone can spot the issue.
I have ubuntu 20.04 server set up on a raspberry pi. The network is configured with NetworkManager for access over my wifi.
I have set it up to allow me to ssh without having to supply a password on my desktop computer and that works reliably.
I am 99% sure I have the right password. However when I tried ssh'ing to it from my laptop it said the password was wrong. When I connected a keyboard and screen to it and tried to log in just after power up, it said the password was wrong.
If I try to set the password:
[onboard:platform2]~$ passwdChanging password for ubuntu.Current password:passwd: Authentication token manipulation errorpasswd: password unchanged[onboard:platform2]~$If I do it this way:
[onboard:platform2]~$ sudo passwdNew password:Retype new password:passwd: password updated successfully[onboard:platform2]~$It is successful. But now when I leave and try to get back in with ssh, disabling the password:
Connection to 192.168.5.27 closed.~ ssh -o PreferredAuthentications=password ubuntu@192.168.5.27ubuntu@192.168.5.27's password:Permission denied, please try again.ubuntu@192.168.5.27's password:Here is my sshd_config:
[onboard:platform2]~$ cat /etc/ssh/sshd_config# $OpenBSD: sshd_config,v 1.103 2018/04/09 20:41:22 tj Exp $# This is the sshd server system-wide configuration file. See# sshd_config(5) for more information.# This sshd was compiled with PATH=/usr/bin:/bin:/usr/sbin:/sbin# The strategy used for options in the default sshd_config shipped with# OpenSSH is to specify options with their default value where# possible, but leave them commented. Uncommented options override the# default value.Include /etc/ssh/sshd_config.d/*.conf#Port 22#AddressFamily any#ListenAddress 0.0.0.0#ListenAddress ::#HostKey /etc/ssh/ssh_host_rsa_key#HostKey /etc/ssh/ssh_host_ecdsa_key#HostKey /etc/ssh/ssh_host_ed25519_key# Ciphers and keying#RekeyLimit default none# Logging#SyslogFacility AUTH#LogLevel INFO# Authentication:#LoginGraceTime 2m#PermitRootLogin prohibit-password#StrictModes yes#MaxAuthTries 6#MaxSessions 10#PubkeyAuthentication yes# Expect .ssh/authorized_keys2 to be disregarded by default in future.#AuthorizedKeysFile .ssh/authorized_keys .ssh/authorized_keys2#AuthorizedPrincipalsFile none#AuthorizedKeysCommand none#AuthorizedKeysCommandUser nobody# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts#HostbasedAuthentication no# Change to yes if you don't trust ~/.ssh/known_hosts for# HostbasedAuthentication#IgnoreUserKnownHosts no# Don't read the user's ~/.rhosts and ~/.shosts files#IgnoreRhosts yes# To disable tunneled clear text passwords, change to no here!PasswordAuthentication yes#PermitEmptyPasswords no# Change to yes to enable challenge-response passwords (beware issues with# some PAM modules and threads)ChallengeResponseAuthentication no# Kerberos options#KerberosAuthentication no#KerberosOrLocalPasswd yes#KerberosTicketCleanup yes#KerberosGetAFSToken no# GSSAPI options#GSSAPIAuthentication no#GSSAPICleanupCredentials yes#GSSAPIStrictAcceptorCheck yes#GSSAPIKeyExchange no# Set this to 'yes' to enable PAM authentication, account processing,# and session processing. If this is enabled, PAM authentication will# be allowed through the ChallengeResponseAuthentication and# PasswordAuthentication. Depending on your PAM configuration,# PAM authentication via ChallengeResponseAuthentication may bypass# the setting of "PermitRootLogin without-password".# If you just want the PAM account and session checks to run without# PAM authentication, then enable this but set PasswordAuthentication# and ChallengeResponseAuthentication to 'no'.UsePAM yes#AllowAgentForwarding yes#AllowTcpForwarding yes#GatewayPorts noX11Forwarding yes#X11DisplayOffset 10#X11UseLocalhost yes#PermitTTY yesPrintMotd no#PrintLastLog yes#TCPKeepAlive yes#PermitUserEnvironment no#Compression delayed#ClientAliveInterval 0#ClientAliveCountMax 3#UseDNS no#PidFile /var/run/sshd.pid#MaxStartups 10:30:100#PermitTunnel no#ChrootDirectory none#VersionAddendum none# no default banner path#Banner none# Allow client to pass locale environment variablesAcceptEnv LANG LC_*# override default of no subsystemsSubsystem sftp /usr/lib/openssh/sftp-server# Example of overriding settings on a per-user basis#Match User anoncvs# X11Forwarding no# AllowTcpForwarding no# PermitTTY no# ForceCommand cvs serverHere is my passed:
onboard:platform2]~$ cat /etc/passwdroot:x:0:0:root:/root:/bin/bashdaemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologinbin:x:2:2:bin:/bin:/usr/sbin/nologinsys:x:3:3:sys:/dev:/usr/sbin/nologinsync:x:4:65534:sync:/bin:/bin/syncgames:x:5:60:games:/usr/games:/usr/sbin/nologinman:x:6:12:man:/var/cache/man:/usr/sbin/nologinlp:x:7:7:lp:/var/spool/lpd:/usr/sbin/nologinmail:x:8:8:mail:/var/mail:/usr/sbin/nologinnews:x:9:9:news:/var/spool/news:/usr/sbin/nologinuucp:x:10:10:uucp:/var/spool/uucp:/usr/sbin/nologinproxy:x:13:13:proxy:/bin:/usr/sbin/nologinwww-data:x:33:33:www-data:/var/www:/usr/sbin/nologinbackup:x:34:34:backup:/var/backups:/usr/sbin/nologinlist:x:38:38:Mailing List Manager:/var/list:/usr/sbin/nologinirc:x:39:39:ircd:/var/run/ircd:/usr/sbin/nologingnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/usr/sbin/nologinnobody:x:65534:65534:nobody:/nonexistent:/usr/sbin/nologinsystemd-network:x:100:102:systemd Network Management,,,:/run/systemd:/usr/sbin/nologinsystemd-resolve:x:101:103:systemd Resolver,,,:/run/systemd:/usr/sbin/nologinsystemd-timesync:x:102:104:systemd Time Synchronization,,,:/run/systemd:/usr/sbin/nologinmessagebus:x:103:106::/nonexistent:/usr/sbin/nologinsyslog:x:104:110::/home/syslog:/usr/sbin/nologin_apt:x:105:65534::/nonexistent:/usr/sbin/nologintss:x:106:111:TPM software stack,,,:/var/lib/tpm:/bin/falseuuidd:x:107:112::/run/uuidd:/usr/sbin/nologintcpdump:x:108:113::/nonexistent:/usr/sbin/nologinsshd:x:109:65534::/run/sshd:/usr/sbin/nologinlandscape:x:110:116::/var/lib/landscape:/usr/sbin/nologinpollinate:x:111:1::/var/cache/pollinate:/bin/falsesystemd-coredump:x:999:999:systemd Core Dumper:/:/usr/sbin/nologinubuntu:x:1000:1003::/home/ubuntu:/bin/bashlxd:x:998:100::/var/snap/lxd/common/lxd:/bin/falsednsmasq:x:112:65534:dnsmasq,,,:/var/lib/misc:/usr/sbin/nologinavahi:x:113:120:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/usr/sbin/nologin