if you don't have upnp on your router or port forwarding set up, you won't have any incoming. p2pool will still work without incoming
I seem to not have any incoming peers for both my BTC and LTC pools, ports have been forwarded for over a month and never had any problems with 11.2 (I updated to 11.3 the other day after managing to read this whole thread over the last month), both pools have had incoming peers since a couple of restarts this week. Since the last reset I seem to not have incoming peers. Any ideas ?
Although I'm not sure, I think you're confusing 2 different things here. Upnp stuff is related to the ability of bitcoin/litecoin/etc client (that is the wallet software) to accept incoming connections from the internet so that you can have more than 8 connections (which is the limit for those users that don't have the appropriate port open/forwarded). I have ports 9332 and 9333 forwarded to the computer that is running litecoin client (in "server" mode) on my home firewall and set "maxconnections=24" in my litecoin.conf, though I'm not sure what's the benefit here, maybe I can "download" the info about the new blocks found faster or something...
But what you're talking about now, the "incoming" peers on the p2pool statistics page, is the number of "miners" connected to your p2pool. If I understand it correctly you'll only see "incoming" there if someone from the internet will start mining on your p2pool.. for that, of course, you'll also have to open/forward the appropriate ports, but the point here is that if you haven't invited anyone to mine on your p2pool node you'll never see anything other than "0" there.
I might be wrong on this, but that's how I see it at the moment. I've got 6 miners at home and usually, if they're all running, I see "Peers: 6 out, 0 in" on my p2pool statistics page. It acts out sometimes and I see "7 out" although I have only 6 miners, might be a p2pool or cgminer bug, but most of the time it's "6 out, 0 in" in my case.