When working in a environment where you are expected to be quite self supporting, which means that you are at least able to spot network problems instead of only being a Oracle consultant you have to have some network tools on your laptop.
It will go without saying you will have to have some ssh client to connect to a prompt. Besides that it always comes in handy to have a port scanner ready for those moments you don’t know which ports are used by Oracle.
One of the other tools I just encountered is a response grapher you can run on a windows client without having to install it. MultiPing Grapher can be downloaded from the ccschmidt website and is freeware. You should check it out whenever you have to monitor a server if he is available and how fast it is responding to network calls.