To manually configure your Yahoo instant messenger client click "Messenger," then select "Connection Preferences."

Select “Connect via a proxy server.” “HTTP proxy” is the default. Note: To use the Yahoo Instant Messenger, Internet Explorer must be configured with the Total Net Shield proxy details. See Configuration Wizard in the Total Net Shield support page for details on adding proxy details to Internet Explorer.

After changing your connection preferences you will need to sign back in to your messenger client.