limiting bandwidth used by SMTP/Internet Mail

limiting bandwidth used by SMTP/Internet Mail

Post by U3Rldm » Tue, 17 May 2005 14:14:02


We've got an Exchange 2003 Server (Win2003 SBS) hooked to a 1500/600 DSL
line. The group sends alot of external email (often w/large attachments) and
when that's going on it hammers the DSL line until the queuing is done. No
only does this affect internet surfing, but also some folks like to work from
home so remote access (VPN) and OWA slow to a crawl when exchange is sending
out the messages.

My questions are...

1) With Exchange is there any way to limit the amount of bandwidth the SMTP
server uses for outgoing mail (ie, can I set it so it only uses
300Kb/s?...That way some bandwith is always available for other functions

2) I set it so that external mail is handed off by Exchange to an external
ISP for deliver (Postini who also does our inbound virus/spam scanning).
When I set that up, I was hoping that on external messages with Multiple
recipents, Exchange would only hand off 1 copy of the message and then the
ISP would take care of deliver to each individual (saving bandwidth for
us)....But, I can tell that if I send 1 5Mb message to 1 person it takes 2
minutes to go out on the dsl line, but if I have 5 recipants listed in the
message it takes 10min (ie its handing the message to the ISP 5x). Is there
anything I can do so it just sends one copy to the ISP?

Thanks in Advance...


limiting bandwidth used by SMTP/Internet Mail

Post by Mark Arnol » Tue, 17 May 2005 15:20:14

On Sun, 15 May 2005 22:14:02 -0700, "Steve"

You can set parameters on the Exchange but none will throttle consumed
bandwidth. A decent router/firewall will do the throttling for you.
Your (2) looks somewhat ugly.


limiting bandwidth used by SMTP/Internet Mail

Post by Ben Hoffma » Tue, 17 May 2005 15:45:53

Hi Steve,

You might also want to look at Quality of Service (QoS) in Windows 2003, if
a new router or firewall is not an option.

Ben Hoffman
MCP (Win2000 Pro/Server & Exchange 2003 Admin)