Container DNS not working #310

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MrUnknownDE · 2026-04-05T17:05:49+02:00

MrUnknownDE commented

2026-04-05 17:05:49 +02:00

Originally created by @dombyte on 1/27/2026

Describe the Bug

The problem I encountered may not be related to Pangolian. However, when I use the Pangolian stack with my firewall configuration, all containers in this stack cannot resolve anything. Testing with different stacks and a BusyBox container revealed that the DNS is working in these cases. My solution was simply to add a DNS configuration to Pangolin and Gerbil in the Docker Compose file.

Environment

OS Type & Version: Debian 13
Pangolin Version: ee-1.15.1
Gerbil Version: 1.3.0
Traefik Version: v3.6
Newt Version:

To Reproduce

iptables Config:

iptables -F INPUT
iptables -P INPUT DROP
iptables -I INPUT -i eth0 -m set --match-set v4_blocklist src -j DROP
iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -p icmp -j ACCEPT
iptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPT

iptables -F DOCKER-USER
iptables -I DOCKER-USER -i eth0 -m set --match-set v4_blocklist src -j DROP
iptables -A DOCKER-USER -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A DOCKER-USER -p tcp --dport 80 -j ACCEPT
iptables -A DOCKER-USER -p tcp --dport 443 -j ACCEPT
iptables -A DOCKER-USER -p udp --dport 51820 -j ACCEPT
iptables -A DOCKER-USER -p udp --dport 21820 -j ACCEPT
iptables -A DOCKER-USER -i eth0 -j DROP

Expected Behavior

Working DNS in the containers, especially for the Traefik Badger plugin, which can't be downloaded without DNS.

*Originally created by @dombyte on 1/27/2026* ### Describe the Bug The problem I encountered may not be related to Pangolian. However, when I use the Pangolian stack with my firewall configuration, all containers in this stack cannot resolve anything. Testing with different stacks and a BusyBox container revealed that the DNS is working in these cases. My solution was simply to add a DNS configuration to Pangolin and Gerbil in the Docker Compose file. ### Environment - OS Type & Version: Debian 13 - Pangolin Version: ee-1.15.1 - Gerbil Version: 1.3.0 - Traefik Version: v3.6 - Newt Version: ### To Reproduce **iptables Config:** ``` iptables -F INPUT iptables -P INPUT DROP iptables -I INPUT -i eth0 -m set --match-set v4_blocklist src -j DROP iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -p icmp -j ACCEPT iptables -A INPUT -i eth0 -p tcp --dport 22 -j ACCEPT ``` ``` iptables -F DOCKER-USER iptables -I DOCKER-USER -i eth0 -m set --match-set v4_blocklist src -j DROP iptables -A DOCKER-USER -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -A DOCKER-USER -p tcp --dport 80 -j ACCEPT iptables -A DOCKER-USER -p tcp --dport 443 -j ACCEPT iptables -A DOCKER-USER -p udp --dport 51820 -j ACCEPT iptables -A DOCKER-USER -p udp --dport 21820 -j ACCEPT iptables -A DOCKER-USER -i eth0 -j DROP ``` ### Expected Behavior Working DNS in the containers, especially for the Traefik Badger plugin, which can't be downloaded without DNS.

MrUnknownDE closed this issue

2026-04-05 17:05:49 +02:00

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Reference: github/pangolin#310