# Could not resolve host: github.com
**URL:** https://meta.discourse.org/t/could-not-resolve-host-github-com/372891
**Category:** Support
**Created:** [July 4, 2025, 7:55am UTC](https://meta.discourse.org/t/could-not-resolve-host-github-com/372891 "2025-07-04T07:55:32Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@jmbeuken](https://meta.discourse.org/u/jmbeuken)
#### Post date: [July 4, 2025, 7:55am UTC](https://meta.discourse.org/t/could-not-resolve-host-github-com/372891/1 "2025-07-04T07:55:32Z")
Hi,
./launcher rebuild app
> fatal: unable to access ‘[GitHub - discourse/discourse: A platform for community discussion. Free, open, simple. · GitHub](https://github.com/discourse/discourse.git/)’: Could not resolve host: [github.com](http://github.com)
but
> root@discourse:/var/discourse# host [github.com](http://github.com)
> [github.com](http://github.com) has address 140.82.121.3
> [github.com](http://github.com) mail is handled by 1 [aspmx.l.google.com](http://aspmx.l.google.com).
> [github.com](http://github.com) mail is handled by 10 [alt4.aspmx.l.google.com](http://alt4.aspmx.l.google.com).
> [github.com](http://github.com) mail is handled by 10 [alt3.aspmx.l.google.com](http://alt3.aspmx.l.google.com).
> [github.com](http://github.com) mail is handled by 5 [alt1.aspmx.l.google.com](http://alt1.aspmx.l.google.com).
> [github.com](http://github.com) mail is handled by 5 [alt2.aspmx.l.google.com](http://alt2.aspmx.l.google.com).
any idea ?
Thanks
* * *
```plaintext
FAILED
--------------------
Pups::ExecError: cd /var/www/discourse && sudo -H -E -u discourse bash -c '
set -o errexit
if [$(git rev-parse --is-shallow-repository) == "true"]; then
git remote set-branches --add origin main
git remote set-branches origin tests-passed
git fetch --depth 1 origin tests-passed
else
git fetch --tags --prune-tags --prune --force origin
fi
' failed with return #
Location of failure: /usr/local/lib/ruby/gems/3.3.0/gems/pups-1.2.1/lib/pups/exec_command.rb:132:in `spawn'
exec failed with the params {"cd"=>"$home", "hook"=>"code", "cmd"=>["sudo -H -E -u discourse git clean -f", "sudo -H -E -u discourse bash -c '\n set -o errexit\n if [$(git rev-parse --is-shallow-repository) == \"true\"]; then\n git remote set-branches --add origin main\n git remote set-branches origin $version\n git fetch --depth 1 origin $version\n else\n git fetch --tags --prune-tags --prune --force origin\n fi\n'", "sudo -H -E -u discourse bash -c '\n set -o errexit\n if [[$(git symbolic-ref --short HEAD) == $version]] ; then\n git pull\n else\n git -c advice.detachedHead=false checkout $version\n fi\n'", "sudo -H -E -u discourse git config user.discourse-version $version", "mkdir -p tmp", "chown discourse:www-data tmp", "mkdir -p tmp/pids", "mkdir -p tmp/sockets", "touch tmp/.gitkeep", "mkdir -p /shared/log/rails", "bash -c \"touch -a /shared/log/rails/{production,production_errors,unicorn.stdout,unicorn.stderr,sidekiq}.log\"", "bash -c \"ln -s /shared/log/rails/{production,production_errors,unicorn.stdout,unicorn.stderr,sidekiq}.log $home/log\"", "bash -c \"mkdir -p /shared/{uploads,backups}\"", "bash -c \"ln -s /shared/{uploads,backups} $home/public\"", "bash -c \"mkdir -p /shared/tmp/{backups,restores}\"", "bash -c \"ln -s /shared/tmp/{backups,restores} $home/tmp\"", "chown -R discourse:www-data /shared/log/rails /shared/uploads /shared/backups /shared/tmp", "[! -d public/plugins] || find public/plugins/ -maxdepth 1 -xtype l -delete"]}
bootstrap failed with exit code 128
```
---
### Author:  [@pfaffman](https://meta.discourse.org/u/pfaffman)
#### Post date: [July 5, 2025, 11:44am UTC](https://meta.discourse.org/t/could-not-resolve-host-github-com/372891/2 "2025-07-05T11:44:15Z")
That’s inside the container, so you could have a docker networking issue, or it could have been a temporary issue?
---
### Author:  [@MichaIng](https://meta.discourse.org/u/MichaIng)
#### Post date: [September 25, 2025, 5:22pm UTC](https://meta.discourse.org/t/could-not-resolve-host-github-com/372891/3 "2025-09-25T17:22:54Z")
Is the container using the hosts `/etc/resolv.conf` by default? If there is a local resolver like `nameserver 127.0.0.1`, I guess that one might not be available from within the container. Unbound is configured to allow queries from all reserved IP ranges, including `172.16.0.0/12` used by Docker containers, so that is not the issue.
Though as we run into the same issue on rebuild, and indeed set up our own Unbound in the meantime, also after removing the the line so that `/etc/resolv.conf` contains again only `nameserver 1.1.1.1` like before, the rebuild still fails at the same point. So maybe it is even cached somewhere? 🤔
From the host, `github.com` can be resolved without issues.
EDIT: Nope, the `/etc/resolv.conf` is not the issue now. I added some debug output:
```plaintext
I, [2025-09-25T17:32:38.092043 #1] INFO -- : > cd /var/www/discourse && cat /etc/resolv.conf
I, [2025-09-25T17:32:38.093195 #1] INFO -- : # Generated by Docker Engine.
# This file can be edited; Docker Engine will not make further changes once it
# has been modified.
nameserver 1.1.1.1
# Based on host file: '/etc/resolv.conf' (legacy)
# Overrides: []
I, [2025-09-25T17:32:38.093221 #1] INFO -- : > cd /var/www/discourse && getent hosts github.com
I, [2025-09-25T17:32:58.111177 #1] INFO -- :
I, [2025-09-25T17:32:58.111456 #1] INFO -- : Terminating async processes
```
EDIT: `apt update` as well hangs forever, a test `curl` fails as well, both as test added to the Discourse templates to check whether network is online. `nameserver 9.9.9.9` does not work either, so looks like the container has no network access, but no idea why.
… EDIT2: Okay, in our case Fail2Ban banned the container IP due to an invalid user account email address it was trying to sent emails to, triggering the Fail2Ban Postfix filter 😄.
Hence, checking Fail2Ban can be one debug step if container has not network.
EDIT3: In Fail2Ban’s jail config:
```plaintext
ignoreip = 127.0.0.1/8 172.16.0.0/12
```
To avoid loopback and Docker IPs being banned.
---
### Author:  [@tobiaseigen](https://meta.discourse.org/u/tobiaseigen)
#### Post date: [October 6, 2025, 8:20pm UTC](https://meta.discourse.org/t/could-not-resolve-host-github-com/372891/4 "2025-10-06T20:20:24Z")