How to add fingerprint to known hosts when SSH is using non-standard port?

[z-nexx]

I have a server that is running a SSH server on a port that is not port 22, for example port 2222. I want to add it as a known host so that I can set up a SFTP pipeline to it, but I can't seem to figure out what "Host address" to put into the form for bitbucket to get the correct fingerprint.

username@hostname doesn't work (I can connect to it using "ssh -P 2222 username@hostname" and I can SFTP to this server using "sftp -P 2222 username@hostname").

The public key on the server is created with the appropriate username@hostname as comment (ssh-keygen -C username@hostname). This is confirmed with "cat ~/.ssh/id_rsa.pub" on the SSH server.

The error I receive in the form is "Unable to fetch fingerprints. Check host SSH connection and try again".

Can't I add a ssh server as a known host when it is running on another port than 22?

[z-nexx · Accepted solution]

I finally found this out myself, the correct syntax is hostname:portnumber.

Maybe specifying a port number is something worth at least mentioning once in the documentation, and maybe at least one example with just a hostname and one with hostname and port on https://confluence.atlassian.com/x/DBuDMg.