Iodine
iodine is a DNS tunnel that encapsulates IPv4 network traffic inside the DNS protocol.[1] This is useful in coffee shops and other public wifi places that use a captive portal but do not block DNS requests.
VTLUUG's DNS tunnel
VTLUUG runs a DNS tunnel on acidburn. Anyone may get an acidburn account and it is required to have an effective tunnel. In addition there is a password to restrict access to authorized members, just contact any officer to get the password.
Using the tunnel requires a TUN/TAP interface and the iodine package.
sudo iodine -f iod.vtluug.org
Then enter the password on the prompt. This sets up a 10.98.10.0/24 tunneled network over DNS. From there ssh into 10.98.10.0, which is acidburn's address and set up a SOCKS proxy:
ssh bobandrob@10.98.10.1 -D 8080
Most web browsers allow you to manually set a SOCKS proxy host & port within the browser settings to proxy all your web traffic through.
As long as the iodine connection was made this will allow you to tunnel your network traffic encrypted around the captive portal.