Enable chat outside Google Apps
The Quick Answer
Your users can chat in the Google Talk network by default.
Update your SRV records to enable chatting via open standards.
Open standards includes users on AOL, Earthlink, Tiscali, Netease, and much more.
Google makes it possible for your Google Apps users to chat with people using other messaging services through a process known as federation. Go to Google Talk and open communications to learn more about federation and who we're federating with.
While we're federating with a large number of service providers, not all services are currently accessible through the Google Talk network, and your users won't be able to chat with users of those services.
If you'd like your users to have the ability to chat with people connected to the Google Talk network through federated networks, you need to edit your Service (SRV) records as shown below. You don't need to edit your SRV records for your users to chat with other Google Apps and Gmail users. SRV records are managed by your domain host. Please contact your domain host to find out if you have access to SRV records and how you can make modifications.
Note: When updating your SRV records with the following information, make sure to replacegmail.com with your domain. However, don't replace google.com.
http://support.google.com/a/bin/answer.py?hl=en&answer=34143
While we're federating with a large number of service providers, not all services are currently accessible through the Google Talk network, and your users won't be able to chat with users of those services.
If you'd like your users to have the ability to chat with people connected to the Google Talk network through federated networks, you need to edit your Service (SRV) records as shown below. You don't need to edit your SRV records for your users to chat with other Google Apps and Gmail users. SRV records are managed by your domain host. Please contact your domain host to find out if you have access to SRV records and how you can make modifications.
Note: When updating your SRV records with the following information, make sure to replacegmail.com with your domain. However, don't replace google.com.
_xmpp-server._tcp.gmail.com. IN SRV 5 0 5269 xmpp-server.l.google.com.Because there are many different domain hosts offering varying options for SRV records, please contact your domain host directly if you need assistance. This includes entering the SRV record data, assigning protocols and weights, and other configuration questions. Some domain hosts will allow you to copy and paste the information above exactly as it's offered while other domain hosts require granular data entry.
_xmpp-server._tcp.gmail.com. IN SRV 20 0 5269 alt1.xmpp-server.l.google.com.
_xmpp-server._tcp.gmail.com. IN SRV 20 0 5269 alt2.xmpp-server.l.google.com.
_xmpp-server._tcp.gmail.com. IN SRV 20 0 5269 alt3.xmpp-server.l.google.com.
_xmpp-server._tcp.gmail.com. IN SRV 20 0 5269 alt4.xmpp-server.l.google.com.
http://support.google.com/a/bin/answer.py?hl=en&answer=34143
