Docker Swarm Networking - no communication to some exposed ports - docker

Question

I have following docker-dompose file:
version: "3.9"
services:
pihole:
container_name: pihole
image: pihole/pihole:latest
ports:
- target: 53
published: 53
protocol: tcp
mode: host
- target: 53
published: 53
protocol: udp
mode: host
# - target: 80
# published: 80
# protocol: tcp
# mode: host
environment:
TZ: 'Europe/Warsaw'
DNS1: 1.1.1.1
DNS2: 8.8.8.8
VIRTUAL_HOST: 'pihole.local'
volumes:
- ./etc/pihole/:/etc/pihole
- ./etc-dnsmasq.d:/etc/dnsmasq.d
dns:
- 1.1.1.1
- 8.8.8.8
cap_add:
- NET_ADMIN
restart: unless-stopped
networks:
- public
networks:
public:
Working solution with docker-compose
Running this with:
docker-compose --file docker-compose-pihole.yml up -d
exposes ports 53 tcp/udp on host ip address
$ nmap 172.30.0.100 -Pn
Starting Nmap 7.80 ( https://nmap.org ) at 2022-01-02 10:42 CET
Nmap scan report for 172.30.0.100
Host is up (0.0038s latency).
Not shown: 998 filtered ports
PORT STATE SERVICE
22/tcp open ssh
53/tcp open domain
and dns resolution is working
$ nslookup google.pl 172.30.0.100
Server: 172.30.0.100
Address: 172.30.0.100#53
Non-authoritative answer:
Name: google.pl
Address: 172.217.16.3
Name: google.pl
Address: 2a00:1450:401b:804::2003
and I'm able to telnet to port 53
$ telnet 172.30.0.100 53
Trying 172.30.0.100...
Connected to 172.30.0.100.
Escape character is '^]'.
NOT Working solution with docker stack deploy
Running the same docker-compose file with
docker stack deploy -c docker-compose-pihole.yml pihole
also exposes 53 port tcp/udp on host IP address
$ nmap 172.30.0.100 -Pn
Starting Nmap 7.80 ( https://nmap.org ) at 2022-01-02 10:46 CET
Nmap scan report for 172.30.0.100
Host is up (0.0022s latency).
Not shown: 998 filtered ports
PORT STATE SERVICE
22/tcp open ssh
53/tcp open domain
however name resolution is not working
nslookup google.pl 172.30.0.100
;; connection timed out; no servers could be reached
telnet to port 53 is closed by remote host
$ telnet 172.30.0.100 53
Trying 172.30.0.100...
Connected to 172.30.0.100.
Escape character is '^]'.
Connection closed by foreign host.
Another strange thing is when port 80 is exposed.
In both cases I can access web UI on port 80 connecting to host IP
I have no idea what's going on and how to fix communication on port 53.

Answer 1

Fixed.
One ENV was missing for pihole:
- DNSMASQ_LISTENING: all
Two days to figure this out!