Windows XP w/SP3.
I've noticed that I have TCP/IP connectivity to IP nodes, say I ping or try to access a CIFS share to a neighbor laptop (lets call him laptop B, i'm laptop A), works fine.
Then, if I try to do the reverse from Laptop B to Laptop A. No good.
No firewall on.
Even weirder....PCap capture actually shows no datagrams hitting the NIC. (Should they appear here even with a software firewall enabled ?. It might be a stupid question. I've never bothered to check. Just assumed it would land in a pcap capture Like an routing/switching ACL.
I might continue here....Something more devastating might be lurking here....In the process of trying to fix a different issue 'RASMAN did not start' event in Event Viewer, and the fact that my PPTP VPN's weren't working (there's a tie there with RRAS and DUN's), I re-installed all my WAN Miniports, and even went so far as doing a repair installation over the top of Windows (slip streamed with SP3).
Result is, PPTP VPN's still don't work. inbound IP connectivity still doesn't work. RASMAN event is fine now though, i.e. no hit in Event Viewer on startup.
The fact that datagrams aren't hitting the NIC (and I have to say, this also occurs with Wireless too, so its not an issue with a particular interface) at all, is really weird, based on what I can see in Wireshark.
I read a KB from Microsoft that under TCP/IP settings there is an Advanced option that talks about TCP/IP filtering. But this setting is on permit all.
I'm stumped ! And I consider myself pretty savvy around Desktop's/technology.....But there are always people smarter than me out there.
Edited by hamluis, 19 November 2010 - 10:31 AM.
Moved from XP forum to Networking ~ Hamluis.