Docker error: HTTP 408 response body: invalid character '<' looking for beginning of value

Question

When I go docker pull hello-world I get the below error message:

Error response from daemon: error parsing HTTP 408 response body: invalid charact

Answer 1

That error message looks like it's coming from a proxy server. From the docker pull documentation

Proxy configuration

If you are behind an HTTP proxy server, for example in corporate settings, before open a connect to registry, you may need to configure the Docker daemon’s proxy settings, using the HTTP_PROXY, HTTPS_PROXY, and NO_PROXY environment variables. To set these environment variables on a host using systemd, refer to the control and configure Docker with systemd for variables configuration.

The link to the instructions for configuring systemd with a proxy is straightforward.

Answer 2

The error message is little misleading. The problem was not that there was invalid character, but the network was misconfigured. I had one LAN interface and one WLAN interface.

LAN interface connects to a router A which forward requests to router B which was connected to internet. While the WLAN interface was directly connected to router B. I forgot to remove the WLAN configuration.

Once I ensured the WLAN interface is removed, things worked smoothly.

In short: Ensured DNS resolution works and that MTU is set right