Maven Proxy Exclusions in settings.xml

Configure a Maven forward proxy with internal-host exclusions using Maven's pipe-separated nonProxyHosts format.

An exclusion copied from a shell's NO_PROXY variable is not automatically valid in Maven. Maven's nonProxyHosts list uses a pipe character between entries, not the comma-separated form common in environment variables.

A proxy entry in the intended user settings can look like this:

<settings>
  <proxies>
    <proxy>
      <id>outbound-proxy</id>
      <active>true</active>
      <protocol>http</protocol>
      <host>203.0.113.10</host>
      <port>8080</port>
      <nonProxyHosts>localhost|*.example.internal</nonProxyHosts>
    </proxy>
  </proxies>
</settings>

This is an illustrative settings fragment around the proxies section. Merge it into an existing settings file rather than replacing unrelated mirrors, servers, and profiles. Use your actual proxy address. If public HTTP proxies are allowed for the repository request, the HTTP proxy list provides candidate host and port pairs.

Match the repository host

Apply exclusions to the hostnames Maven really contacts. An internal repository URL and a public download hostname can need different routes. Do not put an entire repository URL, including its path, into a field meant for host patterns.

Wildcards are supported, but avoid a broad pattern merely to make one failure disappear. Check the intended internal name and a public repository separately after the change.

Find the settings actually used

Maven can combine global and user settings, and an invocation can select an alternate settings file. An IDE can use a different Maven installation or configuration from the terminal. Editing a file that the failing invocation never reads will not change its route.

The proxy's active flag also matters. A correctly spelled host and port in an inactive entry do not establish that Maven will choose it.

Keep the two servers separate

Proxy credentials belong to the proxy entry when that service requires them. Credentials for a private artifact repository belong to the applicable server configuration. Supplying the repository's token does not answer a proxy authentication challenge.

If requests still fail, record the selected repository URL, response or connection error, and effective settings source. First establish whether the request was intended to be proxied or direct; changing the list syntax and changing the endpoint at the same time makes the result harder to interpret.

Mikanda mikatakata