New Firewall - PCs lose ability to ping gateway

[jerryfudd]

Just trying to help a school, but don't have a bunch of time to be there - so wondered if anyone had any ideas.

They recently got a new firewall (Smoothwall to replace a Sophos), and ever since some of the computers (Windows) will stop working on the internet, they cannot ping the gateway. But when that PC is pinged from the smooth wall a couple of times, it will spring back into life.

Running a trace route from that PC just doesn't reach anything and times out immediately.

There are chrome books on the network too (although all wireless) and they don't seem to have any issue apparently.

I know a few steps done - on the Unifi switches the secondary DHCP was set wrong I noticed in the few minutes I was there, that was corrected, and all switches have been rebooted.

DNS/DHCP etc is all handled by internal windows servers, not the firewall.

[Davit2005]

Network Firewall doing what it should by default and blocking anything that is not specifically allowed :-)

 

Modern windows has a habit of using a service (Network Location Awareness aka NLASVC) to identify if a PC has internet connectivity result occasionally the (un)helpful globe and some applications not working. I'd be looking at nlasvc especially as you specify some windows devices are having issues.

Edited September 16, 2022 by Davit2005

[PaddyNewman]

arp -a from CMD, what MAC does it report the gateway as after you attempt to ping it. Does it match your new gateway, or has one of your super helpful switches held on to the old MAC in its arp cache and you get fed bad info.

[ibpalle]

If these are generally devices on the Wifi, make sure that any client separation features, if enabled, exclude the gateway and switch addresses on your network. If the Smoothwall is the gateway and you are using RADIUS for authentication of the clients, there could potentially be another issue in play. Let me know if that's the case.