Recently encountered a weird slowness on one of the subnets at a customer site, https and rdp appear to be extremely slow. Sometimes reporting that certificate revocation information is not available. RDP sessions after initial password prompt also take between 30-60 seconds to connect. SSL and RDP are fine at other sites / subnets. All go to two proxySG’s upstream (set via wpad file). Feels like the slowness is due to some form of security / certificate checking going on, it’s strange that we only see this issue on one subnet as there are lots of others all going to the same ProxySG devices. Haven’t ruled out other area’s of investigation (e.g. group policy, firewall, switches etc.) but we have seen if disabling the certificate revocation checks speed is hugely improved (sometimes a reboot has been needed to kick this in). However it’s not something I’m overly comfortable leaving disabled.
Does anyone have any suggestions on what this could possibly be or how best to troubleshoot? Seen a couple KB’s related to OCSP and CRL but nothing thats a match for intermittent symptoms we’re seeing. We’re upgrading the devices next week (approxy 10 months out of date) and if no better logging a case with Symantec to see if they could help.