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dns2tcp 0.5.2 - DEPRECATED⚓︎

Dns2tcp was developed to tunnel TCP connections over DNS traffic. The
data encapsulation already takes place at the TCP level, so no separate
driver (TUN/TAP) is required. The Dns2tcp client does not need to run
with special privileges.

Dns2tcp consists of two parts: a server-side tool and a client-side
tool. From its configuration file, the server knows a list of resources;
each resource is a local or remote service that listens for TCP
connections. The client listens on a predefined TCP port and forwards each
incoming connection over DNS to the target service.

Using with FreeDNS⚓︎

None of my hosting providers allowed me to set NS records, not even for
a subdomain, which seems to be common. I found out it is also possible
to use FreeDNS for this purpose.

Assuming you have a
(DynDNS) domain name
pointing to your Fritz!Box, lets say fabulous.fritzbox.org, you can do
this:

  1. Register at
    FreeDNS
  2. Create a FreeDNS subdomain:
    • Type: NS
    • Subdomain: anything you like, for example dns2tcp
    • Domain: anything you like, for example strangled.net
    • Destination: for example fabulous.fritzbox.org
  3. Set dns2tcp.strangled.net as DNS name using the dns2tcp WebIF

  4. On the client you should be able to create a DNS tunnel like this
    now:

    dns2tcpc -r ssh -l 2222 -z dns2tcp.strangled.net fabulous.fritzbox.org

  5. If you want a local
    SOCKS
    server to browse the internet:

    ssh root@localhost -p 2222 -D 8765

  6. If you want to use [Polipo?] as http proxy:

    ssh root@localhost -p 2222 -L 8123:localhost:8123

A few notes:

  1. Don't forget to forward port UDP 53 to dns2tcpd, for example
    using AVM-Firewall
  2. dns2tcp works with dnsmasq, if you forward
    to a port other than 53
  3. Use dropbear or OpenSSH as SSH server
  4. Security advice: disable SSH password login and use a certificate to
    login
  5. You can setup dynamic DNS using the regular Fritz!Box interface:
    • Advanced settings | Internet | Permit Access | Dynamic DNS
  6. There is no Windows client available (you could try
    iodine)