My ~/.ssh/config file

ssh_config

#Examples
#To get the MD5 fingerprint instead of SHA256:
# Host example.org
#    FingerprintHash md5
Host ubuntu.dev
     IdentityFile ~/.ssh/ubuntuvm_rsa
Host github.mit.edu
     IdentityFile ~/.ssh/github.mit.edu_rsa
Host github.com
     IdentityFile ~/.ssh/github_rsa
# MIT Athena Dialups
Host *.dialup.mit.edu contents-vnder-pressvre.mit.edu cvp.mit.edu mint-square.mit.edu brym.mit.edu buzzword-bingo.mit.edu gore.mit.edu howe-and-ser-moving.mit.edu has.mit.edu apollo-dome-landing.mit.edu adl.mit.edu biohazard-cafe.mit.edu bl5.mit.edu mass-toolpike.mit.edu i90.mit.edu
        GSSAPIAuthentication yes
        GSSAPIDelegateCredentials yes
# SIPB Office Heads
Host zygorthian-space-raiders.mit.edu zsr.mit.edu coleco-sidewinder.mit.edu csw.mit.edu kid-icarus.mit.edu kid.mit.edu w-a-thornhump-iii.mit.edu thornhump.mit.edu mary-kay-commandos.mit.edu mkc.mit.edu otis-oracle.mit.edu o-o.mit.edu mega-man.mit.edu
        GSSAPIAuthentication yes
        GSSAPIDelegateCredentials yes