SSH public key authentication without DNS entry

Question

Server A thinks it is called foo.bar.com, but actually there's a problem (not in my control) with the DNS registration, so I connect to it at 192.168.1.1. I want to be able to scp from there to server B using public key authentication. I did ssh-keygen, which created a public key ending in "myuser@foo.bar.com" (and installed it in authorized_keys at the far end).

Problem: this public key isn't accepted, perhaps due to a problem with reverse lookup. (I'm reading between the lines here:

debug1: Trying private key: /home/rmmf/.ssh/identity
debug3: no such identity: /home/rmmf/.ssh/identity
debug1: Offering public key: /home/rmmf/.ssh/id_rsa
debug3: send_pubkey_test
debug2: we sent a publickey packet, wait for reply
debug3: Wrote 368 bytes for a total of 1477
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password

...

Is a working DNS entry a prerequisite for pubkey authentication? Do I need to set this up differently? How can I find out if this is actually the problem?

Answer 1

Answering your question, DNS entry is not a prerequisite.

Did you add the content of your private key file on the /home/[your_user]/.ssh/authorized_keys file?

This file works like the locker to which your public key will be matched.

also, set this file permissions to 400 (chmod 400 /home/[your_user]/.ssh/authorized_keys) and be sure that it's owned by your user (chown [your_user] /home/[your_user]/.ssh/authorized_keys )