20 releases (12 breaking)

0.13.0 Jan 19, 2024
0.12.0 Oct 21, 2023
0.11.2 Apr 8, 2023
0.11.1 Dec 23, 2022
0.9.0 Nov 21, 2021

#263 in Command line utilities


1.5K SLoC

ch4 - DNS Client Tool

ch4 is a DNS Client CLI tool built around rsdns.

ch4's primary goal is to expose rsdns's capabilities in a concise manner. It can be used as a simple substitute for dig, with which it tries to be mostly compatible.

ch4 by default uses the tokio async runtime and the corresponding rsdns client. It can be built with all clients and async runtimes supported by rsdns via the same set of features net-tokio, net-async-std, net-smol and net-std.



  1. Built on Linux, Windows, and MacOS
  2. Auto-detection of operating system's default nameserver

Supported RFCs


cargo install ch4

ch4 currently doesn't provide pre-built binaries. See rustrup.rs for installation of cargo and the Rust toolchain.


Nameserver address can be specified with the @ prefix.

$> ch4 @ A docs.rs
; <<>> ch4 0.9.0 git:a9a5dc5 <<>> @ docs.rs
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32221
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1

; EDNS: version: 0, flags:; udp: 512
;docs.rs.                      IN       A

docs.rs.                60     IN       A
docs.rs.                60     IN       A
docs.rs.                60     IN       A
docs.rs.                60     IN       A

;; Query time: 95.678652ms
;; WHEN: Sat, 20 Nov 2021 23:50:24 +0200
;; MSG SIZE rcvd: 100

When nameserver is not specified, it is auto-detected from the OS configuration.

$> ch4 crates.io ANY
; <<>> ch4 0.9.0 git:a9a5dc5 <<>> crates.io ANY
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23571
;; flags: qr rd ra; QUERY: 1, ANSWER: 12, AUTHORITY: 0, ADDITIONAL: 3

; EDNS: version: 0, flags:; udp: 65494
;crates.io.                    IN         ANY

crates.io.              300    IN         TXT    "v=spf1 include:mailgun.org ~all"
crates.io.              300    IN         MX     10 mxb.mailgun.org.
crates.io.              300    IN         MX     10 mxa.mailgun.org.
crates.io.              900    IN         SOA    ns-1064.awsdns-05.org. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
crates.io.              60     IN         A
crates.io.              60     IN         A
crates.io.              60     IN         A
crates.io.              60     IN         A
crates.io.              60     IN         NS     ns-1543.awsdns-00.co.uk.
crates.io.              60     IN         NS     ns-817.awsdns-38.net.
crates.io.              60     IN         NS     ns-217.awsdns-27.com.
crates.io.              60     IN         NS     ns-1064.awsdns-05.org.

ns-217.awsdns-27.com.   20015  IN         A
ns-817.awsdns-38.net.   19938  IN         A

;; Query time: 15.686517ms
;; WHEN: Sat, 20 Nov 2021 23:50:36 +0200
;; MSG SIZE rcvd: 427


ch4's options follow the features exposed by rsdns. The detailed list of options is shown via --help flag.

$> ch4 --help
ch4 0.9.0 git:a9a5dc5
DNS Client

    ch4 [FLAGS] [OPTIONS] [positional]...

    -h, --help
            Prints help information

            Prints build information

            Lists system nameservers

    -V, --version
            Prints version information

    -p, --port <port>
             [default: 53]

    -l, --query-lifetime <query-lifetime>
            query lifetime (in msec). [default: 10000]

    -t, --query-timeout <query-timeout>
            query timeout (in msec). Use 0 to disable. [default: 2000]

    -r, --read <read-path>
            read responses from file

    -s, --save <save-path>
            save responses to file

            Positional arguments ...

            Positional arguments may be specified without any particular order.
            Arguments specified later take precedence.
            Arguments that are not recognized as special are treated as names
            to be queried.

            @<nameserver> - specifies the nameserver IP address.
                            If not specified, the first nameserver from OS
                            configuration is used.

            <qtype>       - query type (A, AAAA, NS ...).
                            An argument matching any of the supported query types
                            is considered as query type. Trailing dot can be
                            used to disambiguate a query name (A.).

            +udp          - sets the Udp protocol strategy. UDP is used by default.
                            Truncated responses are retried using TCP.

            +tcp          - sets the Tcp protocol strategy.
                            Only TCP is used for all queries.

            +notcp        - sets NoTcp protocol strategy. Only UDP is used.
                            Truncated queries are returned as is, without retry.

            +[no]rec      - enables (disables) recursive query.
                            Queries are recursive by default.

            +[no]short    - enables (disables) short output.
                            When enabled, only record data is printed,
                            one record on a line.

            +bufsize=#    - sets the EDNS0 max udp payload size [512, 65535].
                            [default: 4096]

            +[no]edns[=#] - enables/disables EDNS0.
                            Optionally, sets the EDNS version [0, 255].
                            By default, EDNS is enabled with version 0.

            +[no]rust     - enables (disables) rust output.
                            When enabled, prints the response as a Rust array.

            +[no]gen      - forces generic output (RFC 3597 s. 5) on all record
                            types. By default, only unknown record types are
                            formatted this way.

The list of operating system configured nameservers is shown via the --list-nameservers flag.

$> ch4 --list-nameservers

Build information is shown via --info flag.

C:\> ch4.exe --info
build time:          Sat, 20 Nov 2021 23:58:49 +0000
ch4 semver:          0.9.0
git hash:            n/a
compiler:            rustc
rustc:               rustc 1.56.0 (09c42c458 2021-10-18)
cargo features:      net_tokio, tokio
cargo profile:       debug
cargo target:        x86_64-pc-windows-msvc
endianness:          little
pointer width:       64
build system name:   Windows
build os version:    Windows Server 2019 Datacenter
build cpu vendor:    GenuineIntel
build cpu brand:     Intel(R) Xeon(R) CPU E5-2673 v3 @ 2.40GHz


The changelog is maintained in CHANGELOG.md


Licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.


~824K SLoC