Home A - Z
Page Index

An Otter Wiki

Blame

cb1eb9 mb tech 2026-01-19 20:29:32
pi-hole update
1 
# Ubuntu Host Preparation for Pi-hole (Port 53 Conflict Fix)
2
3
## 1. The Issue: Port 53 Conflict
4
By default, Ubuntu runs `systemd-resolved`, which acts as a local DNS stub listener on **Port 53**. Pi-hole also requires Port 53 to function as a DNS server. If `systemd-resolved` is not modified, the Pi-hole container will fail to start with an "address already in use" error.
5
6
## 2. The Fix: Steps to Release Port 53
7
8
### Step 1: Disable the DNS Stub Listener
9
1. Open the resolved configuration file:
150369 mb tech 2026-01-19 20:35:25
updated
10
```bash
11
sudo nano /etc/systemd/resolved.conf
cb1eb9 mb tech 2026-01-19 20:29:32
pi-hole update
12
```
13
2. Locate the line `#DNSStubListener=yes`.
14
3. Change it to:
15
```ini
16
DNSStubListener=no
17
```
18
4. Save and exit (`Ctrl+O`, `Enter`, `Ctrl+X`).
19
20
### Step 2: Fix Local DNS Resolution
21
22
Since the stub listener is disabled, the default `127.0.0.53` DNS entry will no longer work. Point the system to the upstream DNS file instead so the host maintains internet connectivity.
23
24
1. Remove the existing symlink:
25
```bash
26
sudo rm /etc/resolv.conf
27
28
```
29
30
31
2. Create a new symlink to the actual resolv file:
32
```bash
33
sudo ln -s /run/systemd/resolve/resolv.conf /etc/resolv.conf
34
35
```
36
37
### Step 3: Reload and Restart Services
38
39
Apply the changes and reload the daemon to clear any configuration warnings.
40
41
```bash
42
sudo systemctl daemon-reload
43
sudo systemctl restart systemd-resolved
44
45
```
46
47
### Verification
48
49
Check if Port 53 is free (output should be empty or not show `systemd-resolved`):
50
51
```bash
52
sudo lsof -i :53
53
```