I have two public keys, one for some servers and one for others. How do I specify which key to use when connecting to a server?
Assuming you're on a Unix/Linux environment, you can create or edit the file
That config file allows you to establish the parameters to use for each host; so, for example:
Host host1 HostName <hostname_or_ip> IdentityFile ~/.ssh/identity_file1 Host Host2 HostName <hostname_or_ip2> User differentusername IdentityFile ~/.ssh/identity_file2
Note that host1 and host2 can also be not hostnames, but rather labels to identify a server.
Now you can log onto the to hosts with:
ssh host1 ssh host2