When configuring the filtering of instant messaging traffic that is going on under the ICQ protocol, the following is useful to know.
The host names of the instant messaging servers are as follows:
- api.icq.net (Service request server: new since parting from AOL)
- ars.icq.com (File transfer proxy: new since parting from AOL)
- api.oscar.aol.com (Old service request server)
- ars.oscar.aol.com (Old file transfer proxy)
- login.icq.com (For new logon procedure)
- login.oscar.aol.com (For old logon procedure)
ICQ clients log on to a server in an encrypted process that cannot be intercepted by the instant messaging proxy on an appliance.
But after this, an ICQ client asks the service request server for information about the session server, using the magic token received after the logon. Here the instant messaging proxy intercepts. The filtering process then uses another logon procedure after the client name has been announced in the communication with the session server.
In contrast to the vendor Yahoo client, the vendor ICQ client ignores any Internet Explorer connection settings.