I'm not sure if I'm following you correctly here, but let me just clarify a few things here
1. when an IRC client (mIRC) connects to an irc server (e.g. DALnet) it sends it a user name (the email address field in Options) along with other bits of information.
The server then tries to connect to your IP on the identd port to verify the the user name. Whatever is replied by the ident server, is used as your username (username@host) on the irc server. If an ident request isn't possible for whatever reason, the server uses whatever the IRC client supplied as the initial username, and appends ~ in front of it denoting it's an unverified username. Back in the day this made a difference and was considered a security measure, however today it does not.
2. If you're noticing you're unable to get identd requests, therefor signing on with an '~' appended in front of your username, that could be multiple problems.
3. If you're able to sign on with an ident, but regardless of what you change it to in mIRC it's still the samething, that could be due to either
a) another identd server running
b) you're behind a router which is handling all ident requests
c) another computer on your network is handling ident requests
While that may be a little redundant for you, it's just covering all the bases. If you could explain in better detail what your exact problem is, we could help you.
