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DNS Memory consumption on Windows 2008 R2


Windows-Server-2008-R2Q. I did a fresh install of Windows 2008 R2 and my DNS memory consumption is going through the roof. If I reboot, it's ok briefly, but then it goes up again. How can I stop it?

A. There are a lot of discussions about DNS high memory utilization on Windows 2008 R2 floating around. A lot of them point to disabling EDNS, which does not decrease the memory usage. The real problem is in fact due to the ports that DNS opens up: 2500 UDP IPv4 and 2500 UDP IPv6. This is a nice and round number for a busy production DNS server, however, for an internal DNS in a small office this is way too much.

To decrease the number of open ports, run the following command. For an internal DNS, with about 20 people in the office 100 ports is more than enough:

Dnscmd /Config /SocketPoolSize 100

Once command executed, restart DNS service - memory consumption should decrease.

You can also view how many ports you have open:

Dnscmd /Info /SocketPoolSize



Comments (10)
It worked ! Many thanks !
10 Monday, 21 May 2018 06:43
It worked.
But only if run CMD as ADMINISTRATOR !
9 Wednesday, 13 September 2017 13:55
Worked, my DNS (on a new server with many cores) was using 1.5GB, set SocketPoolSize to 1000 and it's now only using 600MB. Thanks!
8 Friday, 01 April 2016 11:22
7 Saturday, 09 January 2016 00:29
Works perfectly! From more than 300MB to only 17. xD
High DNS RAM consumption 2008 R2
6 Monday, 18 March 2013 06:37
Thank you very much. In one of my branch offices, the DC was consuming 308MB RAM with only 3 users. Now using 6MB.
About DNS
5 Sunday, 17 March 2013 02:20
Vishwajeet N
We have around 150 user and we would like to know how many port amount we have to assign for open the same. Sorry we also using sql base application. Pls let us know..Thanks!!!
4 Thursday, 24 January 2013 04:01
Erwin Craps
it works, think its an issue with R2 only.
DNS used 320MB and after setting the ports to 100 only 17MB on my R2 server.
On my SBS2008 port are set to 2500 but dns only uses 17MB.
3 Thursday, 22 December 2011 08:27
Nice article - thanks!
2 Tuesday, 22 November 2011 07:22
If it wasn't for AD I wouldn't use it. Plenty of great alternatives. Yes, RAM is cheap, but I'm running things in VM and consuming resources for no reason is not acceptable.
1 Saturday, 19 November 2011 12:02
Thanks so much! It worked like a charm.
I don't understand this - I have a DNS server running on my Tomato router, with 16 megs in total - and it's fine.
Windows 2008 R2 - 380megs!

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