An odd thing thing about this piece of advice is that it contradicts a lot of the previous advice which is 'don't hardcode stuff' This pattern is questionable for another reason - basing the app's configuration on some other, largely unrelated configuration (in this case, that of the network) can lead to elusive and annoying bugs. Configuration problems are much easier to debug when an application is told what its configuration is rather than trying to magically divine it from its environment.