edit: problem (kind of) solved. It's a problem with the wireless network. no need to answer this.
Up until recently I had no issues at all. I'm not sure what changed to cause this.
Here's the problem: I can connect to the internet from the MBP via either ethernet or wifi just fine.
However, when I try to ping it, I get a response from the ethernet port, but not from the wifi port. This is causing issues like not being able to connect to Charles proxy on the mac, which I was able to do until recently with no problem at all.
I'm using a Late 2011 MBP, OSX 10.7.4, fully updated.