For Gtalk
1. Open Pidgin and select add account.
2. In basic tab enter your user name, domain as gmail.com and also your password.
3. In Advanced select Use old-style SSL, connect port 443 and connect server talk.google.com
4. In proxy tab set Use Environmental Settings
5. Then save settings. This will connect you to the gtalk.
For this to work /etc/environment should have the proxy settings. If not available then add the proxy settings to /etc/environment. It will look like this
http_proxy="http://144.16.192.218:8080/"
https_proxy="https://144.16.192.218:8080/"
ftp_proxy="ftp://144.16.192.218:8080/"
socks_proxy="socks://144.16.192.218:8080/"
HTTP_PROXY="http://144.16.192.218:8080/"
HTTPS_PROXY="https://144.16.192.218:8080/"
FTP_PROXY="ftp://144.16.192.218:8080/"
SOCKS_PROXY="socks://144.16.192.218:8080/"
