dns2doh

Resolve with DNS and generate DOH response

Usage

Usage: dns2doh [options] [input]

–A

Ask for a type A resource. (default)

–AAAA

Ask for a type AAAA resource.

–decode

Decode the DOH input and output the type field and host name from the question part of the DNS packet. The type is output as A or AAAA depending on the field being 1 or 28.

–encode

(default) Encode the host name input to proper DOH message and output it. This is the default action if no option is given. Use --A (default) or --AAAA to control which TYPE to use.

–hex

Show hexdump of the input/output. For debugging the process.

–hosts=FILE

Gives dns2doh a list of host names with type and addresses for which dns2doh will not use dig to resolve but instead use this set of custom handicrafted addresses. Add multiple addresses for a host name by adding multiple lines for it.

Each line in the hosts file should use the format

host type address

It could look like

www.example.com A 127.0.0.1
www.example.com AAAA 2606:2800:220:1:248:1893:25c8:1946

–NS

Ask for a type NS resource.

–onlyq

When encoding a host name, only put the question part in the package. Skip the answer.

–raw

Pass the output without doing base64url encoding.

–help

Show usage message

Examples

$ ./dns2doh daniel.haxx.se
AAAAAQAAAAQAAAAABmRhbmllbARoYXh4AnNlAAABAAHADAABAAEAAAA3AASXZQIxwAwAAQABAAAANwAEl2VCMcAMAAEAAQAAADcABJdlgjHADAABAAEAAAA3AASXZcIx

$ ./dns2doh daniel.haxx.se | ./base64url-decode | hd
00000000  00 00 00 01 00 00 00 04  00 00 00 00 06 64 61 6e  |.............dan|
00000010  69 65 6c 04 68 61 78 78  02 73 65 00 00 01 00 01  |iel.haxx.se.....|
00000020  c0 0c 00 01 00 01 00 00  00 37 00 04 97 65 02 31  |.........7...e.1|
00000030  c0 0c 00 01 00 01 00 00  00 37 00 04 97 65 42 31  |.........7...eB1|
00000040  c0 0c 00 01 00 01 00 00  00 37 00 04 97 65 82 31  |.........7...e.1|
00000050  c0 0c 00 01 00 01 00 00  00 37 00 04 97 65 c2 31  |.........7...e.1|
00000060

$ ./dns2doh --AAAA daniel.haxx.se  | ./dns2doh --decode --hex
= Incoming
00: 00 00 00 01 00 00 00 04 00 00 00 00 06 64 61 6e   |.............dan|
10: 69 65 6c 04 68 61 78 78 02 73 65 00 00 1c 00 01   |iel.haxx.se.....|
20: c0 0c 00 1c 00 01 00 00 00 37 00 10 2a 04 4e 42   |.........7..*.NB|
30: 00 00 00 00 00 00 00 00 00 00 05 61 c0 0c 00 1c   |...........a....|
40: 00 01 00 00 00 37 00 10 2a 04 4e 42 02 00 00 00   |.....7..*.NB....|
50: 00 00 00 00 00 00 05 61 c0 0c 00 1c 00 01 00 00   |.......a........|
60: 00 37 00 10 2a 04 4e 42 04 00 00 00 00 00 00 00   |.7..*.NB........|
70: 00 00 05 61 c0 0c 00 1c 00 01 00 00 00 37 00 10   |...a.........7..|
80: 2a 04 4e 42 06 00 00 00 00 00 00 00 00 00 05 61   |*.NB...........a|
AAAA daniel.haxx.se

$ ./dns2doh --hex daniel.haxx.se
= ALL
00: 00 00 00 01 00 00 00 04 00 00 00 00 06 64 61 6e   |.............dan|
10: 69 65 6c 04 68 61 78 78 02 73 65 00 00 01 00 01   |iel.haxx.se.....|
20: c0 0c 00 01 00 01 00 00 00 37 00 04 97 65 02 31   |.........7...e.1|
30: c0 0c 00 01 00 01 00 00 00 37 00 04 97 65 42 31   |.........7...eB1|
40: c0 0c 00 01 00 01 00 00 00 37 00 04 97 65 82 31   |.........7...e.1|
50: c0 0c 00 01 00 01 00 00 00 37 00 04 97 65 c2 31   |.........7...e.1|
= Header
00: 00 00 00 01 00 00 00 04 00 00 00 00               |............|
= Question
00: 06 64 61 6e 69 65 6c 04 68 61 78 78 02 73 65 00   |.daniel.haxx.se.|
10: 00 01 00 01                                       |....|
= Resources
00: c0 0c 00 01 00 01 00 00 00 37 00 04 97 65 02 31   |.........7...e.1|
10: c0 0c 00 01 00 01 00 00 00 37 00 04 97 65 42 31   |.........7...eB1|
20: c0 0c 00 01 00 01 00 00 00 37 00 04 97 65 82 31   |.........7...e.1|
30: c0 0c 00 01 00 01 00 00 00 37 00 04 97 65 c2 31   |.........7...e.1|