List of the different login methods used by the server list and /server.
0 - Default
1 - SASL (username + password)
2 - SASL EXTERNAL (certificate)
3 - Server Password (/PASS password)
4 - NickServ (/MSG NickServ + Password)
5 - NickServ (/NickServ + Password)
6 - Challenge Auth (username + Password) (HMAC-SHA-256 if available, otherwise HMAC-SHA-1)
7 - Custom (Connect commands)
pass,sasl,external,msg,nickserv can also be used for /server.