.irssi/config

gistfile1.txt

servers = (
  {
    address = "bazookahouse.irc.slack.com";
    chatnet = "slack";
    port = "6697";
    password = "<password>";
    use_ssl = "yes";
    ssl_verify = "yes";
    autoconnect = "yes";
  }
);

chatnets = {
  slack = { type = "IRC"; nick = "<name>"; };
};

channels = (
  { name = "#general"; chatnet = "slack"; autojoin = "Yes"; }
);