Check this article - http://support.microsoft.com/kb/831051/en-us
To test RPC Proxy server run
rpcping -t ncacn_http -s ExchBackEndServer -o RpcProxy=ExchFrontEndServer -P "user,domain,*" -I "user,domain,*" -H 2 -u 10 -a connect -F 3 -v 3 -E -R none -B msstd:server_certificate_subject
To simulate Outlook connection run
RpcPing -t ncacn_http -s ExchBackEndServer -o RpcProxy=ExchFrontEndServer -P "user,domain,*" -I "user,domain,*" -H 1 -F 3 -a connect -u 10 -v 3 -e 6001 -B msstd:server_certificate_subject