I am another user experiencing this precise problem. It started for me about a week ago. We have three computers here running McAfee Security Center. Two are running windows 7 and one is running windows 8.1. All three started experiencing the problem without any change in configuration of any machine. The machine I am on at the moment has Security Center 14.0.1076, Anti-Virus 18.0.208 and Personal Firewall 15.0.194 (09/07/2015). The date on the firewall version seems to correspond with the date I started experiencing this.
Symptoms:
Everything will be working fine. Then the browser, or Outlook, or whatever, will stall because it can't get dns information. In that state any attempt to "nslookup google.ca" from the command prompt, for example, freezes both the nslookup program and the command prompt window is is running in. I finally discovered that if I turn off the Mcafee Firewall and then immediately turn it on again I regain access to dns responses and everything is fine again, including the frozen command prompt window which unfreezes and nslookup then completes the lookup it was asked for. The fix only lasts a while. Then it happens again.
I do not know how to put McAfee Firewall in the state in which it starts doing this, but the fix is completely reproducible: every time this happens, turning the Firewall off and then on again solves the problem - for a while. Before I discovered this "fix" it would be several minutes until the system somehow recovered the ability to get dns information.
The Security History log contains entries like this:
Suspicious incoming network connection blocked
Source IP address: xxx.xxx.xxx.xxx
The PC xxx.xxx.xxx.xxx tried to connect to UDP on Port 50153 on your PC without your permission.
The source IP address is your own DNS server.
The source IP address xxx.xxx.xxx.xxx is indeed one of the two ip addresses listed as dns servers when I run "ipconfig /all" at a command prompt. And note the last line.
It is very clear from this that DNS responses are being blocked by the Firewall even though the software knows that the source is the DNS server that the computer uses to get DNS info.
I did report this: Service Request #: 1780923833
I had a chat with some tech who was obviously anxious to get the the end of his canned script where he says McAfee is not causing the problem and I should contact my ISP.
No, I no I did not "escalate." I have no idea how to do that. Nor do I have the time just now to figure out how to tunnel through the layers of denial McAfee has clearly got set up. I'm hoping that someone here can actually get through to someone at McAfee who is receptive to the possibility that there is a problem with the software.
Some of the entries in the Firewall History Log from during a problem period this morning also show blocking of TCP connections from the IP address of a server that I run out on the internet, with which I was communicating by browser at the time. These are also logged as suspicious connections attempted without my permission, even though the server was clearly responding to a request made by my browser. It is as though Firewall just loses track of what is going on, perhaps as a result of filling up a chunk of memory that then gets cleared when the Firewall is turned off briefly.
I also agree with the earlier comments that the number of people who can and figured out that it is the McAfee software is doing this, and what part causes it, and what it takes to demonstrate that that is the problem, and how to find a forum like this after getting blown off by a "support" tech, is likely a very tiny fraction of the number of people experiencing the problem.
How Many Badges Can You Collect?
