SSH Tunneling on webServer, localhost:80 -> localhost:81, but I received Permission denied (publickey)

I try to make a SSH Tunneling, localhost:80 -> localhost:81
I generate my keys localy and add the .pub on authorized_keys in the cloud.
But I received, Permission denied (publickey).
Ok, not the same key to access with root ( I put user@ip )
and already had a key on the server to authorize access to the terminal by "user"

As I understand it I need to create a new user if I don’t want to use the same key. And even then I could not using the same existing key.

I also didn’t know if it was meant to be
remote port forwarding
or
Dynamic port forwarding

Edit:

/etc/ssh/sshd_config file from the server

# This is the sshd server system-wide configuration file.  See
# sshd_config(5) for more information.

# This sshd was compiled with PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games

# 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 no
#PermitEmptyPasswords no

# Change to yes to enable challenge-response passwords (beware 
issues with
# some PAM modules and threads)
KbdInteractiveAuthentication 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 KbdInteractiveAuthentication and
# PasswordAuthentication.  Depending on your PAM configuration,
# PAM authentication via KbdInteractiveAuthentication 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 KbdInteractiveAuthentication to 'no'.
UsePAM yes

#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
X11Forwarding yes
#X11DisplayOffset 10
#X11UseLocalhost yes
#PermitTTY yes
PrintMotd no
#PrintLastLog yes
#TCPKeepAlive yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#UseDNS no
#PidFile /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 variables
AcceptEnv LANG LC_*

# override default of no subsystems
Subsystem   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 server

I tryng this command to tunneling: ssh -R 81:localhost:80 ubuntu@localhost
To encript data of port 80 and pass to port 81

Terminal response: ubuntu@localhost: Permission denied (publickey).

Asked By: Francisco Ossian

||

Finally understood behind the command.

I thought I needed to use ssh tunnel (the command) on the server, so I was getting the errors ok.

But the command was to be on the client. I didn’t understand that everything is going to happen through ssh port 22. So… my service port
does not need to be exposed.

ssh -L targetPort:localhost:webServerPort -C -N -l user server_ip

this works, runnning in client. SSH use the 22 port to give me webServerPort info.

Answered By: Francisco Ossian
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