SSH Connection to GitHub on a remote server - linux

Question

I'm trying to clone on of my repo GitHub with SSH on my remote server Debian.
In local i have keys id_ed25519.pub and id_ed25519.
I have done an
sh-copy-id -i ~/.ssh/id_ed25519.pub user#host
Checked on remote server and my pubkey is inside authorized_keys.
My pubkey is on my GitHub account too.
On my remote server my sshd_config has :
AuthorizedKeysFile ~/.ssh/authorized_keys
and
PubkeyAuthentication yes
and
PasswordAuthentication no
When doing an ssh -vT git#github.com :
OpenSSH_7.9p1 Debian-10+deb10u2, OpenSSL 1.1.1d 10 Sep 2019
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug1: Connecting to github.com [...] port 22.
debug1: Connection established.
debug1: identity file /root/.ssh/id_rsa type -1
debug1: identity file /root/.ssh/id_rsa-cert type -1
debug1: identity file /root/.ssh/id_dsa type -1
debug1: identity file /root/.ssh/id_dsa-cert type -1
debug1: identity file /root/.ssh/id_ecdsa type -1
debug1: identity file /root/.ssh/id_ecdsa-cert type -1
debug1: identity file /root/.ssh/id_ed25519 type -1
debug1: identity file /root/.ssh/id_ed25519-cert type -1
debug1: identity file /root/.ssh/id_xmss type -1
debug1: identity file /root/.ssh/id_xmss-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.9p1 Debian-10+deb10u2
debug1: Remote protocol version 2.0, remote software version babeld-78794f53
debug1: no match: babeld-78794f53
debug1: Authenticating to github.com:22 as 'git'
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: rsa-sha2-512
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug1: Server host key: ssh-rsa SHA256:.......
debug1: Host 'github.com' is known and matches the RSA host key.
debug1: Found key in /root/.ssh/known_hosts:1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: rekey after 134217728 blocks
debug1: Will attempt key: /root/.ssh/id_rsa
debug1: Will attempt key: /root/.ssh/id_dsa
debug1: Will attempt key: /root/.ssh/id_ecdsa
debug1: Will attempt key: /root/.ssh/id_ed25519
debug1: Will attempt key: /root/.ssh/id_xmss
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /root/.ssh/id_rsa
debug1: Trying private key: /root/.ssh/id_dsa
debug1: Trying private key: /root/.ssh/id_ecdsa
debug1: Trying private key: /root/.ssh/id_ed25519
debug1: Trying private key: /root/.ssh/id_xmss
debug1: No more authentication methods to try.
git#github.com: Permission denied (publickey).

Answer 1

Your remote server doesn't know your private key.
Normally you don't want to copy the private key to a remote server.
But while connecting from your local machine to the remote server, you can use the agent forwarding with
ssh myuser#remoteserver -A
This allows the remote server to use your private key, but without access to the key itself.
Or you can add ForwardAgent yes into your ~/.ssh/config file