OpenSSH allows you to add configuration directives to ~/.ssh/config with aliases for long hostnames or IP addresses:

cat << EOF >> ~/.ssh/config
Host segv                     # desired alias
    HostName          # ip address works too
    Port 22
    User foo
    LocalForward localhost:57005
    IdentityFile ~/.ssh/auxiliary_rsa

This solution is better than using /etc/hosts for obvious reasons. There are a great number of options that allow you choose everything from username to encryption cipher preferences on a host-by-host basis. man ssh_config

I’ve added a nasty little bashism too, as a bonus: