How to Check for DNS Leak on Ubuntu Server Without GUI

[shadowmere24 0]

I'm running ubuntu server 15.10 and I set up a kill switch with airvpn using ufw. I'm concerned that I may have leaks that i'm unaware of, and i don't know how to check to see if I have them or how to avoid them without using a GUI. So how do i check to see if i have a leak without a GUI, and if I do indeed have a leak, how would I fix it?

 

To be clear, I do not want to install a GUI on my ubuntu server just to check this.

 

Thank you!

[zhang888 1066]

Linux will query the servers from /etc/resolv.conf.

 

If you want to make an explicit rule in order to make sure no other application is changing these servers

in /etc/resolv.conf (although if it's a single user system nothing should ever alter it) you can add these

extra iptables rules:

 

iptables -t nat -A PREROUTING -s 0/0 -p udp --dport 53 -j DNAT --to 10.4.0.1

iptables -t nat -A PREROUTING -s 0/0 -p tcp --dport 53 -j DNAT --to 10.4.0.1

 

These rules will make sure that any application that uses even it's own DNS implementation,

which is again very rare, will be redirected to AirVPN's resolver instead.

[shadowmere24 0]

Would typing those into the terminal permanently add them as rules? Also, my setup is simply using transmission to torrent while hosting a plex media server to serve up the content i torrent. From what you've said, it seems like it is unlikely that i would be leaking anything. Is that a fair assessment considering that i'm only worried about leaking my ip while torrenting? And does a dns leak from my media server (or any other service i have) make my torrenting traffic vulnerable to prying eyes?

 

Thanks for the help!

[cm0s 118]

what zhang888 said