Windows Server Core Docker Containers networking problem

Question

I have 2 containers created via docker compose with the following settings:

docker-compose.yml File:

version: "3.7"
services:
    web:
        image: img_web
        container_name: cont_web

    svcs:
        image: img_svcs
        container_name: cont_svcs
        depends_on:
            - web

Dockerfile for img_web:

FROM mcr.microsoft.com/dotnet/framework/aspnet:4.8-windowsservercore-ltsc2019
WORKDIR /inetpub/wwwroot

Dockerfile for img_svcs:

FROM mcr.microsoft.com/dotnet/framework/aspnet:4.8-windowsservercore-ltsc2019
WORKDIR /inetpub/wwwroot

After docker-compose up -d, and from cont_svcs container, I'm able to:

1. Ping cont_web by IP

2. Ping cont_web by hostname (container id: bf4001be1e84 autogenerated.)

BUT I CAN'T Ping the cont_web container by its alias (web)

I inspected both containers, I can see in the network sections the following:

"Networks": {
            "test_default": {
                "IPAMConfig": null,
                "Links": null,
                "Aliases": [
                    "bf4001be1e84",
                    "web"
                ],
...

Both containers are connected to the 'test_default' driver.

NB: Even I can't ping the web machine by its "web" alias name within the machine itself.

I would greatly appreciate your help and feedback.

Thanks Sam

Answer 1

That's because Netbios resolution works for primary name. you can try to add 2nd Netbios name through registry: https://www.techrepublic.com/blog/the-enterprise-cloud/adding-multiple-netbios-names-for-windows-servers/

alternatively i'd recommend make a 2nd Cname record in DNS and doing the resolution with static names (might not be acceptable to you for your docker containers)