72 lines
No EOL
2.6 KiB
Markdown
72 lines
No EOL
2.6 KiB
Markdown
# Setting up Hostname resolution
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Dynamic hostname resolution in modern linux distributions is provided by *Avahi*.
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## Installation
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Refer to the documentation for your linux distribution. The following instructions are for arch linux, but the process should be roughly the same on other distributions as well.
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`sudo pacman -S avahi`
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Then enable the service. Here you can choose between *enabling the service* or *using socket activation*.
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**A.** Socket activation: avahi will only be started when a program or service requests it.
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`sudo systemctl enable avahi-daemon.socket`
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**B.** Enabling the service: avahi will always be active, even when no service has requested it.
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`sudo systemctl enable --now avahi-daemon.service
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*systemd-resolved* might conflict with avahi. You can manually go through its config and disable the multicast DNS resolver/responder, or you can disable the service entirely:
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`sudo systemctl disable systemd-resolved`
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You also need the following package:
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`sudo pacman -S nss-mdns`
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## Configuration
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Edit the file `/etc/nsswitch.conf` and change the `hosts` line to include `mdns_minimal [NOTFOUND=return]` before `resolve` and `dns`.
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Here is an example:
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```
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hosts: mymachines mdns_minimal [NOTFOUND=return] resolve [!UNAVAIL=return] files myhostname dns
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```
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If you experience slowdowns in resolving `.local` hosts (or you do not want to use IPv6) try to use `mdns4_minimal` and `mdns4` instead of `mdns_minimal` and `mdns` respectively.
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### Fix issue with NSS-MDNS caused by systemd-resolved
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If you didn't disable *systemd-resolved* entirely, and instead only disabled multicast DNS resolution, please follow this step. If you disabled the service entirely you can skip this.
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First, make sure you have the `host` command available on your system. On arch linux, it is installed by the `bind` package in the `extra` repository.
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`sudo pacman -S bind`
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Then, run the following command and hope that it returns `NXDOMAIN`:
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`host -t SOA local`
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If the host did respond with `NXDOMAIN`, you don't need to follow the rest of the steps in this section.
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If it didn't, continue reading.
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Replace `mdns_minimal` in `/etc/nsswitch.conf` that you added earlier, with the full `mdns` module:
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```
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hosts: mymachines mdns [NOTFOUND=return] resolve [!UNAVAIL=return] files myhostname dns
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```
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And then create `/etc/mdns.allow` with the following content:
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```
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.local.
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.local
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```
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Note that this solution might break reverse lookups, such as `traceroute`. To fix this, change back `mdns` to `mdns_minimal`. This will unfortunately sacrifice your dynamic hostname resolution ability.
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Other than that, you are done. |