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Very slow internet access - 31.Jul.2007 2:00:46 PM

johnny_mango

Posts: 42
Joined: 17.Jan.2007
Status: offline

Hi there,

I have just installed ISA 2006 for a client, and it is having a massive impact on the speed of conections to the Internet. Besides, there are occasional DNS errors in IE.
The ISA server has its external NIC with a public IP, and default gateway as the router with the access to the internet.
Internal NIC with internal IP address, no DG and internal DNS servers, both of which are configured with forwarders for public name resolution.

I have the internal NIC at the top of the binding list.
The external card, having read that it would be a good idea, had auto for the speed setting, which I changed to 100 full, to match the setting of the switch, but this has resulted in worse performance.

The speed problema affects around 10 users (just as well i didn�t roll it out for all at the same time) who are a mixture of Web Proxy, SecureNAT and Firewall clients, all of whom have the same problem, and it is not for a small selection of sights.

Can anyone give me some guidance before my neck is placed on the block?

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RE: Very slow internet access - 6.Aug.2007 8:25:44 PM

tshinder

Posts: 47490
Joined: 10.Jan.2001
From: Texas
Status: offline

Make sure Path MTU discovery is enabled on the ISA Firewall

Make sure the browsers are configured to use HTTP 1.1 through proxy connections.

HTH,
Tom

_____________________________

Thomas W Shinder, M.D.
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Prowess Consulting http://www.prowessconsulting.com/
Blog: http://blogs.isaserver.org/shinder/

GET THE NEW ISA 2006 Book!: http://tinyurl.com/2gpoo8

(in reply to johnny_mango)

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RE: Very slow internet access - 10.Aug.2007 5:37:31 PM

johnny_mango

Posts: 42
Joined: 17.Jan.2007
Status: offline

I shall give that a try and let you know, Tom, thanks very much.
I was seeing just there that this (MTU) is a problem with Windows Server 2003 SP1 and ISA Server 2004, according to the Microsoft KB.
Strangely it has seemed to only occur once I set up the wpad entry in DNS.

(in reply to johnny_mango)

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RE: Very slow internet access - 13.Aug.2007 9:24:27 AM

tshinder

Posts: 47490
Joined: 10.Jan.2001
From: Texas
Status: offline

So things seemed to have fixed themselves?

Tom

_____________________________

Thomas W Shinder, M.D.
Sr. Consultant/Technical Writer
Prowess Consulting http://www.prowessconsulting.com/
Blog: http://blogs.isaserver.org/shinder/

GET THE NEW ISA 2006 Book!: http://tinyurl.com/2gpoo8

(in reply to johnny_mango)

Post #: 4

RE: Very slow internet access - 13.Aug.2007 4:32:21 PM

johnny_mango

Posts: 42
Joined: 17.Jan.2007
Status: offline

I have only just configured it today. I created the registry key for the MTU Discovery in the ISA Server and created an access rule for the MTU protocol.

If this fails, I will revise the access rules I have created as there are 2 involving large numbers of URL�s which apply to all users with an exception, and also the same ISA Server has SurfControl installed.

(in reply to johnny_mango)

Post #: 5

RE: Very slow internet access - 20.Aug.2007 6:55:01 PM

johnny_mango

Posts: 42
Joined: 17.Jan.2007
Status: offline

Hi there,

Just to give some quick feedback. I enabled MTU path discovery on the ISA 2006, and created access rules to allow the traffic.
I also disabled 2 access rules which blocked access to certain domains and URL�s - many 100�s of URL�s. Additionally, I disable any daily reports that were running.

However, the performance continued being really slow, however, changing my connection to the ISA 2004 I also noticed it slow, although not quite as much. Thinking it over, the ISA 2006 is connected to another firewall on the external NIC, different model to the ISA 2004, before it connects to the switch and router, from where it send internet-bound traffic.

Anyway, the client has agreed that the internet access is too slow from both servers, and will probably check with the ISP as to why it is suddenly so slow, with no great increase in users. That apart, we did some testing with the McAfee page, for a client connected as Web proxy to each server, and it suggested the ISA 2004 was twice as slow, however downloading the same file on each server, proved the contrary. Added to that, we did some more tests at various times, and the access time is significantly worse when there are more users, as one might expect, so that rules out performance or bad configuration on the ISA Server 2006.
If anyone has similar problems I suggest you repeat tests similar to mine at various times of the day, to have hard data to enable further investigation.

(in reply to johnny_mango)

Post #: 6