Re: problems with KB951746

Bypassing ISA and not having it can be two different things. Since that seems to be the one common denominator between all four systems, and you administrate all four, I'm gonna take a stab and say that they all share a similar configuration. And I'm 'hoping' the problem lies somewhere in there. If this was a widespread problem, you'd see a lot more reports of it, so I have to focus on what is unique, but shared, with your systems.

Unfortunately, I don't run ISA on SBS and haven't for many years (it has always bugged me!) although I run it standalone in front of SBS quite a bit. So bear with me, I'm running off of old memories and sortof 'imagining' the differences between running it standalone vs how running it on SBS would be different. With that in mind, break it down for me....HOW are you bypassing ISA during these tests? And secondly, you mentioned you cannot call CSS because you cannot have the fix installed in production....so how have you done the testing you've already done at the level of detail you've indicated?

-Cliff

"Gary Karasik" <gkarasik@xxxxxxx> wrote in message news:uFkR2u6$IHA.5660@xxxxxxxxxxxxxxxxxxxxxxx


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GaryK


You originally posted this a couple weeks ago as a different thread. "Attn: Susan Bradley" or somesuch. As I recall, it was ONE SBS server and as of the end of the week last week, you had decided to contact Microsoft CSS. So, my questions are:

1) What did CSS say?

I tried 800-PCSAFETY, but that's really consumer oriented, and they weren't much help. I haven't called CSS. There's no real point because I can't have the fix in place during production--the internet is practically unusable--and there are no symptoms outside of production for CSS to troubleshoot.

2) Did you make changes to the other three servers within the last week?
I'm trying to pinpoint why the problem has spread...

No changes. The problem hasn't spread--only my awareness of it. One of them was having DSL problems, and I attributed the Inet slowdown to that. But as soon as the DSL troubles were cleared up, it became obvious they were having the same problem. On another one the office was closed for a couple of weeks--clients attending a convention--so again there was no load on the system and no obvious symptoms. The fourth is a small office full of really sweet people who didn't want to bother me about the slow internet response times.


3) Do any of the four servers run *without* ISA? I'd like to troubleshoot on a network as 'clean' as possible...

Sadly, no. But I can bypass ISA and reproduce the problem.

4) Do all four servers connect to the internet using the same ISP?

No.

I appreciate your focusing on this.

GaryK



"Gary Karasik" <gkarasik@xxxxxxx> wrote in message news:ug9WDl0$IHA.1180@xxxxxxxxxxxxxxxxxxxxxxx
Agreed. But in this case it's moot. The issue persists even if both firewalls are bypassed.

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GaryK


"Cliff Galiher" <cgaliher@xxxxxxxxx> wrote in message news:hIadnXIUU8UcpjvVnZ2dnUVZ_j6dnZ2d@xxxxxxxxxxxxxx
Depends on how aggressive the firewall is with its intrusion prevention measures. Blocking legitimate IP addresses responding on ports the firewall doesn't expect will cause problems. And three or more people using the net will cause the firewall to block IPs more rapidly. Never *assume* that the problem isn't somewhere. Test and verify...test and verify... :)

-Cliff

"Gary Karasik" <gkarasik@xxxxxxx> wrote in message news:u7%23gyc0$IHA.3756@xxxxxxxxxxxxxxxxxxxxxxx
Also, if this were a firewall issue, I think it would be there all the time, not just when the system is under load.

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GaryK


"Cliff Galiher" <cgaliher@xxxxxxxxx> wrote in message news:I5OdnRWuYKkGijvVnZ2dnUVZ_uqdnZ2d@xxxxxxxxxxxxxx
Gary,

I doubt the patch, or SBS, is the problem here. What I suspect is happening is that the patch is doing what it is supposed to do. But one of the things the patch does is cause the source port to be randomized. If your firewall is not configured to allow DNS traffic from a random source port then your recursive DNS requests are being stopped at the firewall...and you'll get the symptoms you describe. It is also possible, but less likely, that your ISP's DNS servers are misconfigured and are unable to reply on odd source ports.

So this is where I'd start....look at your network perimeter and see if you can verify there is a firewall issue.
Then, if you are CONFIDENT that you are okay there and the speed issue remains, reconfigure SBS (CEICW) and point it to another DNS server that is known to be patched and working (openDNS is a good option here).

Let me know if that helps,

-Cliff

I'm fairly confident you'll be able to fix the issue from there.
"Gary Karasik" <gkarasik@xxxxxxx> wrote in message news:%236rvj2y$IHA.5660@xxxxxxxxxxxxxxxxxxxxxxx
Hi,

I can't decide how to proceed with getting this problem solved. Wien the server-side DNS-vulnerability patch (951746) is installed, all my SBS2K3 systems are exhibiting the same problem: extremely show internet access when the system is under load, meaning when three or more clients are trying to access the internet at once.

With the patch uninstalled everything returns to normal. This is not resolved by reserving ports as one fix suggests.

The problem seems to be that DNS can't resolve quickly when the patch is installed. Sometimes it is so slow that the system times out. I've tried different forwarders, different DNS servers, and root hints only. If the patch is installed, nothing helps.

Someone has posted a message about this in the SBS private forum, but he isn't getting much help.

My indecision stems from the fact that no symptoms show if there is no load, so if I call CSS after hours I can't show them any symptoms, and I don't want to load the patch during a work day because access is so slow that client work slows to a virtual standstill, the remote branches connections to Exchange server stop responding, and local clients can't do any work that involves the internet.

I think I'm just going to have to live with this and hope that MS comes up with a fix for someone else and I hear about it.

Maybe someone here can suggest an approach, because I'm stumped as to how to proceed.

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GaryK













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Relevant Pages

  • Re: problems with KB951746
    ... I doubt the patch, or SBS, is the problem here. ... It is also possible, but less likely, that your ISP's DNS servers are ... reconfigure SBS and point it to another DNS server ...
    (microsoft.public.windows.server.sbs)
  • Re: problems with KB951746
    ... Do any of the four servers run *without* ISA? ... What I suspect is happening is that the patch is doing what it is supposed to do. ... If your firewall is not configured to allow DNS traffic from a random source port then your recursive DNS requests are being stopped at the firewall...and you'll get the symptoms you describe. ... It is also possible, but less likely, that your ISP's DNS servers are misconfigured and are unable to reply on odd source ports. ...
    (microsoft.public.windows.server.sbs)
  • Re: problems with KB951746
    ... What I suspect is happening is that the patch is doing what it is supposed to do. ... If your firewall is not configured to allow DNS traffic from a random source port then your recursive DNS requests are being stopped at the firewall...and you'll get the symptoms you describe. ... It is also possible, but less likely, that your ISP's DNS servers are misconfigured and are unable to reply on odd source ports. ... Then, if you are CONFIDENT that you are okay there and the speed issue remains, reconfigure SBS and point it to another DNS server that is known to be patched and working. ...
    (microsoft.public.windows.server.sbs)
  • Re: problems with KB951746
    ... reconfigure SBS and point it to another DNS server that ... I've tried all sorts of forwarders and root hints and DNS servers. ... I'm fairly confident you'll be able to fix the issue from there. ... With the patch uninstalled everything returns to normal. ...
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    ... If you include the ISP's DNS servers as well as the SBS Server DNS address on the workstations, they may and most likely will, experience issues with locating resources on the SBS server. ... Ideally, I'd like the DHCP server in SBS to dole out it's address, and my ...
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