Packages and Binaries:
This is a piece of software that lets you tunnel IPv4 data through a DNS server. This can be usable in different situations where internet access is firewalled, but DNS queries are allowed.
How to install:
sudo apt install iodine
- debconf | debconf-2.0
- udev | makedev
Tunnel IPv4 over DNS
[email protected]:~# iodine -h iodine IP over DNS tunneling client Usage: iodine [-v] [-h] [-f] [-r] [-u user] [-t chrootdir] [-d device] [-P password] [-m maxfragsize] [-M maxlen] [-T type] [-O enc] [-L 0|1] [-I sec] [-z context] [-F pidfile] [nameserver] topdomain Options to try if connection doesn't work: -T force dns type: NULL, PRIVATE, TXT, SRV, MX, CNAME, A (default: autodetect) -O force downstream encoding for -T other than NULL: Base32, Base64, Base64u, Base128, or (only for TXT:) Raw (default: autodetect) -I max interval between requests (default 4 sec) to prevent DNS timeouts -L 1: use lazy mode for low-latency (default). 0: don't (implies -I1) -m max size of downstream fragments (default: autodetect) -M max size of upstream hostnames (~100-255, default: 255) -r to skip raw UDP mode attempt -P password used for authentication (max 32 chars will be used) Other options: -v to print version info and exit -h to print this help and exit -f to keep running in foreground -u name to drop privileges and run as user 'name' -t dir to chroot to directory dir -d device to set tunnel device name -z context, to apply specified SELinux context after initialization -F pidfile to write pid to a file nameserver is the IP number/hostname of the relaying nameserver. if absent, /etc/resolv.conf is used topdomain is the FQDN that is delegated to the tunnel endpoint.
Start an iodine IPv4-over-DNS tunnel
[email protected]:~# iodine-client-start -h 'iodine-client-start' starts an iodine IP-over-DNS tunnel. Usage: iodine-client-start [option] -h, --help Print help and exit -v, --version Print version info and exit Invoking the program without options attempts to set up and configure an iodine IP-over-DNS tunnel using the configuration in the file /etc/default/iodine-client or by querying the user. It tries to figure out the right way to set things up by observing the network, and if all else fails by guessing. QUICK CONFIGURATION Put two lines in the file /etc/default/iodine-client subdomain=your.tunnel.sub.domain passwd=password_for_that_tunnel or invoke the script with those environment variables set: env subdomain=xxx passwd=xxx iodine-client-start If these are not set, the script will query the user for them. DETAILS The configuration file consists of lines which are either comments starting with '#', or settings of the form VAR="val". Valid VARs are: subdomain Sample value: your.tunnel.sub.domain (no default, must be set) passwd Sample value: password_for_that_tunnel (no default, must be set) testhost Hostname to ping when testing if network is working (default: slashdot.org) bounce_localnet Take the local network down and then up again before starting tunnel (default: false) test_ping_localnet Test if the local network is working by pinging the gateway (default: true) test_ping_tunnel Test if the iodine tunnel is working after it has been set up by pinging the host at the other end (default: true) test_ping_final Test if the tunnel is working after everything is ostensibly set up by trying to ping an external host (default: true) default_router IP address of router on the local network---should be found automatically, set this if that fails and the program guesses wrong. interface Interface to use (e.g., eth1, eth0, etc) for connection to DNS server used for the iodine tunnel---should be found automatically, set this if that fails and the program guesses wrong. mtu Set if tunnel MTU needs to be manually changed (lowered). Should not be necessary anymore, as recent versions of iodine negotiate an appropriate MTU during tunnel setup. But if that negotiation does not happen, or if you are using an older version of iodine, the default tunnel MTU is 1024, and if the local DNS server restricts to 512 byte packets you might need to use an MTU of 220. skip_raw_udp_mode Set "-r" option in iodine command line. With this option, iodine does not try to establish a direct UDP socket to the iodine server on port 53. (default: true). continue_on_error Set if the script should continue even if a command fails. Use to test script when running as non-root. Defaults to false if running as root, true otherwise.
Tunnel IPv4 over DNS
[email protected]:~# iodined -h iodine IP over DNS tunneling server Usage: iodined [-v] [-h] [-c] [-s] [-f] [-D] [-u user] [-t chrootdir] [-d device] [-m mtu] [-z context] [-l ip address to listen on] [-p port] [-n external ip] [-b dnsport] [-P password] [-F pidfile] tunnel_ip[/netmask] topdomain -v to print version info and exit -h to print this help and exit -c to disable check of client IP/port on each request -s to skip creating and configuring the tun device, which then has to be created manually -f to keep running in foreground -D to increase debug level (using -DD in UTF-8 terminal: "LC_ALL=C luit iodined -DD ...") -u name to drop privileges and run as user 'name' -t dir to chroot to directory dir -d device to set tunnel device name -m mtu to set tunnel device mtu -z context to apply SELinux context after initialization -l ip address to listen on for incoming dns traffic (default 0.0.0.0) -p port to listen on for incoming dns traffic (default 53) -n ip to respond with to NS queries -b port to forward normal DNS queries to (on localhost) -P password used for authentication (max 32 chars will be used) -F pidfile to write pid to a file -i maximum idle time before shutting down tunnel_ip is the IP number of the local tunnel interface. /netmask sets the size of the tunnel network. topdomain is the FQDN that is delegated to this server.
Updated on: 2022-Aug-05