Apparently you're hosting your code in github and using it from locations that are not always in your company intranet. Basically, then, you have the following solutions available:
- Host a nexus (or similar) repository on your own public server, with authentication. This way it would be accessible from whereever you want it to. It can also be done on Amazon, for example.
- Use some of the free, open, hosted solutions. For example, Sonatype offers free hosting for open-source projects.
- As already suggested, you can host your maven repo also on github - don't store it on your code repo, create a separate project for it!
- Or.. just pay for hosting. There should be some supported solutions if you're willing to pay for it.
Any of these should work for you. From the way you described your situation, possibly option 3 is what you want. Any case, have them somewhere else than in your code repository.
EDIT: possibly I also overlooked the most self-evident solution for a closed-source development, so this would be an alternative 5. From a comment:
The smartest thing to do in this case would be to just put the
repository behind your firewall and allow people from the outside to
access it over your VPN. You could set up a publicly accessible
service that requires all users to present some sort of credentials,
but why open your repository to the outside world (and all the risks
that entails) when you don't really need anyone from outside your
organization to use it? Assuming of course, you have a VPN - but if
you have remote employees, you should probably have a VPN so they can
access your internal services securely.
This sounds reasonable, if your repo is not a public one.