Configure git to use IPv4 instead of IPv6 by default

Question

Checking the environment variables and also HTTP configuration options does not reveal something. Is there a way to do this?

Answer 1

The more generic solution (that also works for BSD) is to edit the global /etc/ssh/ssh_config or per-user ~/.ssh/config and add/replace the entry:

AddressFamily any 

with

AddressFamily inet

You can also set this for just a single host:

Host example.com
    AddressFamily inet

Answer 2

With git 2.8 (March 2016), you can force git fetch/push/clone to use IPV4 or IPV6.
(for git pull, see below Git 2.16, Q1 2018)

See commit c915f11 (03 Feb 2016) by Eric Wong (ele828).
^{(Merged by Junio C Hamano -- gitster -- in commit e84d5e9, 24 Feb 2016)}

connect & http: support -4 and -6 switches for remote operations

Sometimes it is necessary to force IPv4-only or IPv6-only operation on networks where name lookups may return a non-routable address and stall remote operations.

-4, --ipv4:

Use IPv4 addresses only, ignoring IPv6 addresses.

-6; --ipv6:

Use IPv6 addresses only, ignoring IPv4 addresses.

---

Update Git 2.16 (Q1 2018): Contrary to the documentation, "git pull -4/-6 other-args" did not ask the underlying "git fetch" to go over IPv4/IPv6, which has been corrected.

See commit ffb4568 (19 Nov 2017) by Shuyu Wei (``).
^{(Merged by Junio C Hamano -- gitster -- in commit c2b6135, 27 Nov 2017)}

---

With Git 2.29 (Q4 2020), "git fetch --all --ipv4/--ipv6^(man)" forgot to pass the protocol options to instances of the "git fetch" that talk to individual remotes, which has been corrected.

See commit 4e735c1 (15 Sep 2020) by Alex Riesen (ar-cetitec).
^{(Merged by Junio C Hamano -- gitster -- in commit 6854689, 22 Sep 2020)}

fetch: pass --ipv4 and --ipv6 options to sub-fetches

^{Signed-off-by: Alex Riesen}

The options indicate user intent for the whole fetch operation, and ignoring them in sub-fetches (i.e. "--all" and recursive fetching of submodules) is quite unexpected when, for instance, it is intended to limit all of the communication to a specific transport protocol for some reason.

Answer 3

In 99% of cases, you should not be doing this. The real answer to the question is fix your IPv6 connection.

Failing that, you can edit /etc/gai.conf to prefer IPv4 over IPv6. gai.conf modifies the behaviour of getaddrinfo(), which almost all IPv6–supporting applications use to resolve hostnames.

Almost all systems ship with a copy of /etc/gai.conf within their glibc or libc package. If it is missing from /etc, usually I find a template copy is lurking somewhere within /usr/share/doc, for you to copy into /etc and modify accordingly.