I will keep this short and sweet. We have servers in our environment that have multiple IP addresses assigned to a single NIC. That’s normally just fine. However on occasion I will have very strange issues occur where essentially all networking appears to be working and yet web browsing won’t work. I can ping my default gateway, ping other systems in the same subnet, telnet out on port 80 and 443, etc, etc. But the network connectivity still behaves oddly. What’s the issue?

It all has to do with networking logic decisions made many years ago (I believe as far back as Windows Server 2000) by someone at Microsoft. (more…)