We have an ASA for our IPSec VPN service that has been up and running for some time. We ran into an issue at a trade show this week in which we could connect to our VPN using the trade show wifi but could not access anything behind our firewall (computers, servers, etc.) yet simply tethered to a cell phone, and using the VPN we could then access what we needed.
I suspect some sort of conflict with the local trade show wifi subnet and our internal subnet behind the firewall, although both connections are using NAT.
The trade show DHCP is handing out 172.16.0.0/16 addresses and the subnet we're trying to access behind the VPN is 172.16.128.0/22. VPN connections are assigned addresses from a separate pool (10.4.99.0/24).
When using the wifi and VPN I am able to connect, and ping the gateway interface of the ASA, but nothing beyond. When using cellular and VPN I am able to ping the gateway and pass traffic to services behind it.
Any thoughts on how this might be resolved? We have not run into this before and the VPN has been in use for several years.
I often have this conflict. Check if you have a default route on the Pc when you are on the wifi that goes through the gateway of the local router. Add more specific route to go through the gateway of your VPN adapter. e.g.
route add .....
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