We had an issue the other day where we did not know if a new server would be able to reach out to the WSDL that our old server was able to hit. While we were fairly confident that we had a problem, I was introduced to a new OS command: curl. Used by itself with no switches, and just the WSDL link after the command as the first argument, retrieved the WSDL definition on our old server without a problem. On the new server the command was not successful because it was not able to reach the destination!
Reading up on the Wikipedia page linked above it appears that this command will download the source of any webpage offered in the argument, including saving the source code off locally with the right switches! This may be a rare tool that we have in our toolbox, but the one time you need it is the one time you will be glad you have it!