Create a proxy repository with Version Policy of release ( the default maven-central repo is configured this way ).
When an inbound request arrives at a path that looks like a SNAPSHOT type request, NXRM will still handle the request as if it is a valid path the repository could support. This will subsequently send a corresponding request outbound from NXRM to a remote that a NX admin is already expecting does not support SNAPSHOT versions.
The whole point of having a version policy defined is to throw out and reduce the number of repositories to process a request for a group repo request, and also prevent needless requests that will always( or are expected to) 404 at the remote.
NXRM 2, this returns 404 and does NOT trigger an outbound request ( how it is supposed to work): http://localhost:8081/nexus/content/repositories/central/com/example/example/0.1.028-SNAPSHOT/maven-metadata.xml
NXRM 3, this does trigger an outbound request:
To help enforce the version policy to releases, create a routing rule with Mode BLOCK and include the pattern Matcher of
then assign that to the repository with the release version policy. You may still encounter issue: NEXUS-12249
For a Maven format repository, if the version policy of the repo is set to RELEASES, throw out the repository with that policy as early as possible when processing an inbound request that is for a SNAPSHOT request.