Azure Pipelines Agent .proxybypass URL Patterns

A self-hosted Azure Pipelines agent can hold proxy bypass rules in a .proxybypass file in its root directory. Each line is an ECMAScript regular expression matched against a URL.

For example, a rule for one internal feed host can look like:

^https?://packages[.]internal[.]example(?::[0-9]+)?(?:/|$)

The expression matches HTTP or HTTPS URLs for that host, with an optional numeric port. The boundary after the hostname avoids also matching a longer name such as packages.internal.example.other-domain.

This is the agent installation’s file, not a file placed arbitrarily in the source checkout. Its syntax also differs from a comma-separated NO_PROXY value. Copying a shell wildcard such as *.internal.example into a regular-expression field does not preserve the same meaning.

Then identify who downloads the package

The agent’s built-in source and artifact operations use its proxy configuration. Tasks can retrieve exposed proxy information through the task library and apply it to their own HTTP clients.

A task invoking an external NuGet, dotnet or curl process introduces another consumer. Confirm how that task supplies proxy and bypass settings to the tool. A correct agent rule does not establish that every independent package client has read it.

Keep the internal feed URL in the diagnostic record, including its scheme and port. Test the rule against the URL being contacted, then examine the task/client configuration responsible for that request.