LLMNR not working on Windows 7

1

I tried LLMNR name resolution on two different Windows 7 Home computers and one Windows 7 Professional computer.

I deactivated the firewall (Kaspersky) on the one computer to ensure that this is not a firewall issue. "Network Discovery" (which is required for LLMNR) is enabled for both private and public network connections.

Both Wireshark and Netmon traces show that the computers will send multicast LLMNR requensts over the network to resolve the IP address of a computer. However none of the computers will ever send a response packet!

Why?

Martin Rosenau

Posted 2013-12-27T14:20:52.123

Reputation: 562

Answers

0

Make sure the local Windows firewall is allowing the response packets as well.

In addition, in the local Group Policy (gpedit.msc) change

Computer Configuration\Administrative Templates\Network\DNS Client\Turn off Multicast Name Resolution

to Disabled

Finally, make sure they are all on the same network and that any local network firewall (for instance if they are going through a wifi router) isn't blocking anything.

Then reboot the computers and try again.

TheCleaner

Posted 2013-12-27T14:20:52.123

Reputation: 2 302

Thanks for the quick answer. Unfortunately on "Home" variants of Windows 7 there is no "gpedit.msc" but they only have the "discovery" setting. LLMNR is explicitly set to "allowed" in the Windows firewall so I think that this is also not the issue. – Martin Rosenau – 2013-12-27T17:35:07.497

Asked: 2013-12-27T14:20:52.123

Viewed: 1 095 times

Active: 2015-12-30T19:55:04.197