Hi everyone,
I am experiencing a frustrating issue with my DEC2700 appliance and I need some help to troubleshoot it.
My Setup:
A virtualized instance running on VMware.
A physical DEC2700 appliance (LAGG 2x10Gb)
Both are configured as a cluster/HA pair. I recently resolved some LAGG (Link Aggregation) issues on the physical appliance, and now both units seem properly configured.
The Symptom:
When I switch the internet traffic to the VMware VM, everything works perfectly.
When I switch traffic over to the DEC2700 appliance, everything seems to work fine.
However, some websites completely stop loading. Users start reporting connectivity issues, yet there are absolutely no logs showing dropped packets or blocks in the firewall. It behaves as if silent filtering is occurring.
The issue is 100% reproducible on specific websites: I get a blank page (or endless loading), while the exact same URL loads instantly when routing through the VM.
What I have ruled out so far:
DNS Issue: It does not seem to be DNS-related. DNS resolution works perfectly fine on the DEC2700, and I can successfully resolve the IPs of the problematic websites.
My Suspicions:
It feels like an SSL/TLS inspection or certificate validation issue that kicks in after a short delay.
Given that I just fixed a LAGG configuration, could this be a MTU / MSS clamping issue causing packet fragmentation drops? MTU is already set to 1500 on the LAGG , but not on "VLAN child Interface"
Has anyone encountered a similar behavior on a DEC2700 or OPNsense setup? Where should I look if the firewall logs are completely clean?
Thanks in advance for your help!
Little update, if can help
I fix MTU and MSS to 1500 to all interfaces : still KO
i change MSS to 1450 to all interfaces : still KO
thx for help ;p