Container Listener not working on IP Address from server - Only works on IP from the Docker Network

SUMMARY

I am running a Zabbix Server container, but I am not being able to communicate on its listening port - Locally even.

OS / ENVIRONMENT / Used docker-compose files

This is the script I am currently using to run it:

docker run -d --name zabbix-server \
 --restart always \
 --link zabbix-snmptraper:zabbix-snmptraps --volumes-from zabbix-snmptraper \
 -p 192.168.1.248:10052:10051 \
 -e MYSQL_DATABASE="zabbix" \
 -e MYSQL_USER="zabbix" \
 -e MYSQL_PASSWORD="aro@123" \
 -e ZBX_LISTENPORT=10052 \
 -e ZBX_HOUSEKEEPINGFREQUENCY=12 \
 -e ZBX_LOGSLOWQUERIES=1000 \
 -e ZBX_STARTPOLLERSUNREACHABLE=1 \
 -e ZBX_STARTPINGERS=5 \
 -e ZBX_STARTTRAPPERS=1 \
 -e ZBX_STARTDBSYNCERS=3 \
 -e ZBX_STARTDISCOVERERS=4 \
 -e ZBX_STARTPOLLERS=10 \
 -e ZBX_TIMEOUT=30 \
 -e ZBX_VALUECACHESIZE=32M \
 -e ZBX_CACHESIZE=48M \
 -e ZBX_MAXHOUSEKEEPERDELETE=432000 \
 -e ZBX_ENABLE_SNMP_TRAPS=true \
 -e MYSQL_ROOT_PASSWORD="my_root_pass_of_mysql..." \
 -e DB_SERVER_HOST="mysql-server" \
 -e DB_SERVER_PORT="3306" \
 -v /etc/localtime:/etc/localtime:ro \
 -v /mnt/dados/zabbix/external_scripts:/usr/lib/zabbix/externalscripts \
--network=zabbix-net \
zabbix/zabbix-server-mysql:5.4-ubuntu-latest

CONFIGURATION

The code block of commands is being run on a Debian 11.

STEPS TO REPRODUCE

Basically, the container is UP and running.

The passive queries are all working - I can gather data from Zabbix to other Zabbix Agents, SNMP, etc.

The problem happens when I try to do a active query from outside to Zabbix Server itself... (Active queries.)

My deduction was that the docker container did not create the necessary routes for this, so I must specify something or there is some configuration missing.

EXPECTED RESULTS

When doing a telnet to 10052 on my Zabbix Server, the expected result is a OK Connected.

ACTUAL RESULTS

Locally, on my own Zabbix Server, when I did:

sudo telnet 192.168.1.248 10052

I got telnet: Unable to connect to remote host: Connection refused

Crazy thing is that when doing this on the IP address of the DOCKER NETWORK, (Got the IP from docker inspect zabbix-server "IPAddress": "172.18.0.4"):

sudo telnet 172.18.0.4 10052

> Trying 172.18.0.4...
> Connected to 172.18.0.4.

It worked. So there is a routing problem with this container.

But most containers when running create the rules or at least show it in logs or docs. how to do it.

But I could not find this anywhere...

Can you please help me?

I am on this for more than two weeks and do not know what to do anymore.

If this is in the wrong section or "flow", please direct me to the correct place to this.
I really appreciate the help.

Edit 1

Here is the output TCPDUMP gave me:

16:28:12.373378 IP 192.168.17.24.55114 > 192.168.1.248.10052: Flags [S], seq 2008667124, win 64240, options [mss 1460,nop,wscale 8,nop,nop,sackOK], length 0

As you can see, packets are coming through and arriving to the Docker Server.

I tried adding the following rule to IPTables to see if it solved it:

sudo iptables -t nat -A PREROUTING -p tcp --dport 10052 -j DNAT --to-destination 172.18.0.4:10052 -m comment --comment "Redirect requests from IP 248 to the container IP"

But it did not work. Or I created this wrongly.

To list the rules I used the command:

sudo iptables -t nat -v -L PREROUTING -n --line-number

It was created all fine.

While you configured Zabbix to listen on port 10052 (-e ZBX_LISTENPORT=10052), you mount the host port 10052 to the containers port 10051 instead (-p 192.168.1.248:10052:10051).

Use -p 192.168.1.248:10052:10052 to make it work.

docker run -d --name zabbix-server \
 --restart always \
 --link zabbix-snmptraper:zabbix-snmptraps --volumes-from zabbix-snmptraper \
 -p 192.168.1.248:10052:10052 \
 -e MYSQL_DATABASE="zabbix" \
 -e MYSQL_USER="zabbix" \
 -e MYSQL_PASSWORD="aro@123" \
 -e ZBX_LISTENPORT=10052 \
 -e ZBX_HOUSEKEEPINGFREQUENCY=12 \
 -e ZBX_LOGSLOWQUERIES=1000 \
 -e ZBX_STARTPOLLERSUNREACHABLE=1 \
 -e ZBX_STARTPINGERS=5 \
 -e ZBX_STARTTRAPPERS=1 \
 -e ZBX_STARTDBSYNCERS=3 \
 -e ZBX_STARTDISCOVERERS=4 \
 -e ZBX_STARTPOLLERS=10 \
 -e ZBX_TIMEOUT=30 \
 -e ZBX_VALUECACHESIZE=32M \
 -e ZBX_CACHESIZE=48M \
 -e ZBX_MAXHOUSEKEEPERDELETE=432000 \
 -e ZBX_ENABLE_SNMP_TRAPS=true \
 -e MYSQL_ROOT_PASSWORD="my_root_pass_of_mysql..." \
 -e DB_SERVER_HOST="mysql-server" \
 -e DB_SERVER_PORT="3306" \
 -v /etc/localtime:/etc/localtime:ro \
 -v /mnt/dados/zabbix/external_scripts:/usr/lib/zabbix/externalscripts \
--network=zabbix-net \
zabbix/zabbix-server-mysql:5.4-ubuntu-latest