we had a new nokia IP 320 box with checkpoint NG with AI. Our setup is: LAN->Firewall->Router. Our LAN consists of Exchange server and ISA server in caching only mode. STATIC NAT is configured for ISA server and exchange server on the checkpoint firewall. Rule configured in firewall for ISA server is to allow http,https,dns,yahoo messenger service. User's can access the internet through ISA server.no issues with internet access and e-mail flow. we want users to use yahoo messenger with "use proxy" settings with ISA servername as the proxy server and port 8080. but it is not working with this settings. if i connect my pc to access the firewall directly i can login to yahoo messenger i.e with rule defined on checkpoint firewall like - my pc as source, any as destination and yahoo messenger as service. i can login with "no proxies" settings. We dont want to use this settings. We want all users to use our ISA server in cache only mode to be configured as proxy in yahoo messenger. I think there is something missing in the ISA server to forward the Request to Firewall. NOTE: we have defined Allow protocol rule for any request on ISA server. I Hope experts here can help me on this. what else needed to be configured on. its urgent.. thanks