We are facing an issue where we will experience source port exhaustion on our MWGs if we leave things as is. The problem is that Microsoft Office 365 is being rolled out in our organization and Microsoft has predicted Armageddon for our proxy infrastructure. The problem is more of a TCP limitation than a hardware limitation on the MWG as the MWG's are barely breathing from a resource standpoint being beefy fully loaded 5500C appliances.
The O365 clients will open anywhere between 10 and 30 long lived TCP connections to various O365 servers on the Internet. Since there is a limit on the number of source ports a single IP address can have (65535 theoretical but more like 50000 in reality) we can only support about 1500 to 2000 O365 users per MWG. So... my question is... is it possible to add more logical IP's to the interface to "load balance" across them to give us more source port capacity? We are configured with a single interface with a single IP. All client traffic and server side traffic goes across this single interface currently.
Yes, you can add multiple IP's. Where you configure the interface there is something call IP Alias. Just add more there.
Also, I personally dont believe Microsoft and their sizing. We act as an ISP for a number of schools who make heavy use of O365. We have 8 MWG5500's, and definitely more than 2k users per server.