ASA5505, Denied UDP connections from Vista PC

[leeann92571]

I have a vista pc, on SBS domain, static ip/dns. disabled the IPV6, only IPv4 running. Intermittently the network connection drops and the ASDM syslog shows internet connection denied...flags PSH ACK interface inside and then also deny inbound UDP.....to DNS query. Idisabled the autotuning/scaling on the vista, but I dont know what to do on the router side. I am really rusty on the ASA and need some direction please!! thanks!

[merryllem]

I've seen this problem on a pix before. Basically the problem is the size of the incoming DNS packets. Check this link out. It might lead you the right direction

http://news.hping.org/comp.security.firewalls.archive/5815.html

[leeann92571]

I did try the no fixup protocol dns to disable the max length, but still had a problem. I did also see the client had netbios enabled, so that has been disabled also, bust the Vistaclient is the only one who keeps dropping the connection and the router is deny its connections to the server.

[merryllem]

Try increasing the max lenght to 768 or 1024