Prevent (or at least detect) Man in the Middle Attack from Firewall

TheBoss

My employer installed a new-generation firewall and to my surprise it blocked a site while I was connected to an OpenVPN session. Is there any way I can configure OpenVPN to prevent (or at least detect and fail) a man in the middle attack?

Presently I am set as:

TinCanTech

You could try TOR

TheBoss

Yes, I could do TOR for browser, however I need apps access too. Apparently my employer doesn't want me to meet girls, lol.

TinCanTech

Hang out here for a while .. you will meet loads of girls !

dazo

This new firewall ... is that some software which got rolled out on your computer as well? Or just the more common network wide firewall installed on that site? This is important to understand, as it helps figuring out what is happening on your VPN client side.

Initially, this sounds like --redirect-gateway not being functional (something changed the network routing on your client); or that DNS requests are not sent to the DNS server you would normally expect. But I'm grasping straws here, we need to understand where this firewall you speak of is installed.

ecrist

Verify that your DNS requests are traversing the tunnel through the VPN. Many of these next-gen firewalls will intercept the interesting DNS traffic in an attempt to reroute to their "naughty" web page informing of the invalid access.

TheBoss

I am using the IOS client, and the firewall I refer to is is part of the local network infrastructure. Is there any reason my DNS request should not go through the tunnel? How can I tell with IOS? :-(

bbuckm

TheBoss wrote How can I tell

https://www.dnsleaktest.com