Long time lurker, but today I encountered an odd problem that will bug me until resolution :-)
It seems to be presenting as a one-way ping issue from one server to a failover cluster.
All machines are running Windows Server 2008 R2 with IPV6 disabled. The windows firewall service is disabled.
Lay of the land:
Report Server - VMWare Virtual Machine using E1000 NIC. Nothing special - IP, Subnet, Gateway and routing table all appear sane.
SQL 2008R2 Active/Passive Failover cluster - Each has 7 configured NICs- 3 iSCSI, and the remaining 4 bound to 2 IPs with BACS. One NIC Team is used for local traffic and the other as part of the failover cluster. The failover cluster has a VIP.
All was working fine last week. All machines are on the same subnet. Today, the report server couldn't ping the VIP of the failover cluster. It could ping both nodes without issue, using both non-storage IP addresses.
The SQL failover cluster could ping the report server without any issue.
I can ping the SQL VIP from any other machine, vindicating it in my mind.
I tried rebooting the report server in the event that TCP/IP was misbehaving to no avail. What ended up working was changing the Report Server IP address - As far as I know there are no host rules in place on the switch (Catalyst 3750).
What could cause this one? I'd say the ARP table was cleared after the report server rebooted, and the IP address shouldn't have become stale on the DB cluster... looking for someone with more networking know-how than I :-)