I have done the following

• I have searched the existing issues
• If possible, I've reproduced the issue using the 'main' branch of this project

Steps to reproduce

Env

Machine: M1 Macbook Air
OS: MacOS 15.5

container version:

container --version
container CLI version 0.2.0 (build: release, commit: 3b5c253)

IPs info

• container ls > buildkit container's IP ADDR: 192.168.79.2
• ifconfig > bridge100 inet: 192.168.79.1
• container inspect buildkit | jq '.[0].configuration.dns.nameservers': 192.168.79.1

Steps to reproduce

Originally this happened when I tried to build an image (see details below) with a Dockerfile which has a RUN command curl -LO https://github.com/yarnpkg/yarn/releases/download/v1.22.19/yarn_1.22.19_all.deb. Afterwards, I found it also happened with the following steps:

1. Start a container container run --rm -it ubuntu
2. In container's bash

apt-get update && apt-get install curl -y
curl https://github.com
# curl: (6) Could not resolve host: github.com

Note: I also tried curl https://www.apple.com in container and it worked.

Current behavior

More details about the steps to reproduce

With the IPs above, running container build with a Dockerfile having a command apt-get update worked and resolved ubuntu.com on my side, but failed to resolve github.com when my Dockerfile has a RUN command curl -LO https://github.com/yarnpkg/yarn/releases/download/v1.22.19/yarn_1.22.19_all.deb.

When the buildkit nameserver IP is consistent with my subnet, not sure why it could resolve ubuntu.com with apt-get but failed to resolve github.com with curl?

Dockerfile FYR:

FROM ubuntu

RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
    DEBIAN_FRONTEND=noninteractive apt-get install -yq --no-install-recommends \
        unzip curl gnupg libgfortran5 libgbm1 tzdata netcat \
        libasound2 libatk1.0-0 libc6 libcairo2 libcups2 libdbus-1-3 libexpat1 libfontconfig1 \
        libgcc1 libglib2.0-0 libgtk-3-0 libnspr4 libpango-1.0-0 libx11-6 libx11-xcb1 libxcb1 \
        libxcomposite1 libxcursor1 libxdamage1 libxext6 libxfixes3 libxi6 libxrandr2 libxrender1 \
        libxss1 libxtst6 ca-certificates fonts-liberation libappindicator1 libnss3 lsb-release \
        xdg-utils git build-essential ffmpeg && \
    mkdir -p /etc/apt/keyrings && \
    curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg && \
    echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_18.x nodistro main" | tee /etc/apt/sources.list.d/nodesource.list && \
    apt-get update && \
    # Install node and yarn
    apt-get install -yq --no-install-recommends nodejs && \
    curl -LO https://github.com/yarnpkg/yarn/releases/download/v1.22.19/yarn_1.22.19_all.deb \
        && dpkg -i yarn_1.22.19_all.deb \
        && rm yarn_1.22.19_all.deb

# ...

Error message:

72.02 Preparing to unpack .../nodejs_18.20.6-1nodesource1_arm64.deb ...
72.02 Unpacking nodejs (18.20.6-1nodesource1) ...
73.83 Setting up nodejs (18.20.6-1nodesource1) ...
73.85   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
73.85                                  Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0curl: (6) Could not resolve host: github.com

Expected behavior

curl https://github.com should work in the container.

Environment

- OS: macOS 15.5
- Container: 0.2.0 (build: release, commit: 3b5c253)
- Machine: M1 Macbook Air

Code of Conduct

• I agree to follow this project's Code of Conduct