p2pool: Is it setup correctly? "???" in efficiency I have configured p2pool, bitcoind and bfgminer for mining, and everything appears to be working normally (i.e., no errors are reported).

However, I've been mining for over three days already at 2GH/s without obtaining a single share. This is what p2pool output says:

&gt; Shares: 0 (0 orphan, 0 dead) Stale rate: ??? Efficiency: ??? Current
&gt; payout: 0.0000 BTC


I am worried about the question marks for efficiency. Is this normal? Should it be relevant, I am in a managed network, so I can't have any incoming peers (which as I understand, are not strictly required).
You won't see a value there until you mine a share, so seeing a ??? is normal for the moment. The efficiency is a measure of how many shares have been counted in the share chain verses the ones you have found. 

At 2GH/s you should be expecting to see a share soon, given an average of 2 days 8 hours to find a share at 2GH/s at difficulty 88800 (the current for p2pool).