I'm working with a customer to resolve some issues with their network, and I have a hunch that their issues is that their firewall is just overwhelmed. However, I've never actually found any information on exactly what to look for to diagnose an overwhelmed firewall.
Does anyone have any sources or just knowledge of what this looks like? The symptoms they are having is that their external clients are suffering from intermittent connectivity, the PAs are HA paired, but one of them is dead and a reboot of the firewall temporarily solves this issue. However, it's strange that only their external clients would suffer from this issue.
They have larger firewalls scheduled to upgrade the older ones, but logistics have prevented this from happening just yet, so here I am.
What do overworked firewalls look like?