We have two Win 2003 Servers (physical) running ISA 2006 SP1 in a NLB cluster (ISA-integrated). Both have 2 interfaces (Int: 172.16.210.x and Ext: 172.16.214.x). Both NICs of ISA1 reside on Secondary Switch and ISA2 on Primary switch. HA have been tested
in past at Switch and ISA level. Oftenly, ISA2 start sending FTP traffic using Ext NIC (172.16.214.x) instead of Int NIC which results in FTP time out as the handshake won't complete between ISA and FTP server and external user fails to FTP. NLB is enabled
on Ext interfaces with NAT on FW to forward traffic from FW to ISA Ext interface.
When it happens, this is only specific to FTP traffic and rest of published applications are not affected. Simple reboot of ISA2 resolves it. Both Nodes are identical in terms of OS, networking, routing information etc. ISA2 was formatted to downgrade from Win 2003 Ent to Std edition few months ago. ISA BPA gives no relevant failure. Both Nodes are in full sync and changes replicate. Kindly suggest a solution for this intermittent issue.
When it happens, this is only specific to FTP traffic and rest of published applications are not affected. Simple reboot of ISA2 resolves it. Both Nodes are identical in terms of OS, networking, routing information etc. ISA2 was formatted to downgrade from Win 2003 Ent to Std edition few months ago. ISA BPA gives no relevant failure. Both Nodes are in full sync and changes replicate. Kindly suggest a solution for this intermittent issue.