High network latency between firewall and Dell clients

  • Hi

    We have a rather unusual issue since we changed the default gateway of a number of Dell clients to the VLAN CARP address of our PFSense firewall cluster.

    Normally, latency between devices separated by the firewall is 1ms-3ms. However, after about 15-20 minutes of moderate traffic crossing the firewalls to the Dells, the latency between devices across the firewall increases to approximately 18ms and the latency to the Dells specifically rockets to >400ms with peaks of over 2000ms. Traffic flowing to the Dells slows to a trickle whereas traffic to other clients is only moderately affected.

    I have head of issues with pfSense and Broadcom NICs which these Dells have, but can't find mention of issues with Broadcom based network clients.

    The firewall cluster is running pfSense 2.2 on Supermicro hardware (Intel Atom Rangeley CPU, 16GB RAM, 8 x Intel i350 NIC ports). The cluster connects to the internal switches (Cisco 2960S) via a 4x1G LAGG trunk carrying 4 VLANS.

    The two Dells are R720 XDs, one of which has Windows 2008 R2 on it, the other is an ESX host, which is hosting a number of Windows guests. The Windows guests are also affected. The Dells have fault tolerant NIC pairs to the switches.

    Latency between devices in the same VLAN is not affected (<1ms) - only latency between devices which traverse the firewalls via the VLAN CARP addresses is affected, and only the Dells are affected significantly. The Dells are also the only devices which have Broadcom NICs, all the other servers use Intel NICs. There is no latency to the firewalls non-CARP address on the same VLAN.

    Any assistance would be appreciated?

    Kind regards

    Windows is fully patched

  • Hello,

    Did you find something ?

    I have a similar configuration and have same troubles. It's quite temporary on my side but sometimes the ping between two systems in two different vlans can go from 0.200ms to 5/15 ms without any reason.

    Thank you