Windows Server - ISA 2000 with High Speed ADSL

Asked By JohnG

12-Sep-07 04:21 AM

Hi All,

I have moved a couple of my clients to high speed adsl (up 20Mbps download),
when I had the modem connected directly to the desktop a speed test showed a
very fast 20Mbps.

However when I do the speed test through SBS ISA 2000 as a normal shared
connection its maximum seems to be 8Mbps. I have tried several times on two
different networks and the same maximum 8Mpbs shows.

Does ISA 2000 throttle the speed? any suggestions (other than not using ISA
2000!) how to get the full speed?

12-Sep-07 09:28 AM

Do you have a router connected to the ADSL modem that might have a limit of
8 Mpbs?

--
Merv  Porter   [SBS-MVP]
============================

17-Sep-07 03:58 AM

No. Maybe I should clarify it's a modem/router. The same router connected to
the desktop achieves around 20Mbps, connected through ISA it caps at 8Mbps.

I have doubled checked configurations, I have been installing ISA since day
dot and never had speeds of greater than 1.5Mbps so never really seen this.
I have two independent sites doing this so it sort rules out a problem on
one of them?

Thanks for any help.

17-Sep-07 08:56 AM

Is the hardware (CPU, RAM, etc.) of the server on the "low end"?

ISA Server 2000 Performance Best Practices
http://www.microsoft.com/technet/archive/security/prodtech/isa/isaprfbp.mspx?mfr=true

--
Merv  Porter   [SBS-MVP]
============================

18-Sep-07 07:13 AM

No, these are IBM x3500 servers, Xeon cpu, 2Gb ram, gigabit nics etc.

This doesn't appear to be a performance problem, it caps at almost 8Gb on
all servers every time regardless of load.

Just installed it on SBS 2003 (R2) with ISA 2004 (sp2) and it's doing the
same thing.

Speedtest.net all on all 3 servers shows around 8Mpbs, yet connect directly
to the router shows double the speed??

18-Sep-07 08:19 AM

Not sure what's going on John.  Maybe you can post this over in the ISA
forums.  Tom Shinder may have an answer.

http://forums.isaserver.org/

--
Merv  Porter   [SBS-MVP]
============================