Setting Receive Limit on Exchange 2000 Server

[Nitin Nair]

We have a request to set the email size receive limit on the Exchange server
from external email address to 28MB. Our environment is: Exchange 2000 Server
with SP3 - build: 6249.4.

We made the necessary change on the servers. We have set the limit in below
locations:
1. Global settings: In Exchange Manager Global Settings > Message Delivery >
right click it > Properties > Defaults > Receiving Message Size - No Limit
(By Default)

2. SMTP Virtual Server Settings: Administrative Groups > First Admin Group
> Routing Group > Servers > Servername > Protocols > SMTP > SMTP Virtual
Server > Right Click > Properties > Messages > Limit Message Size to - 28672
KB on all Virtual servers.

3. Connector Setting: Administrative Groups > First Admin Group > Routing
Group > Routing Group Name > Connectors > Right Click > Properties > Content
Restrictions > Allowed Sizes > Changed to 28672 KB but no luck.

Though the above setting is not required coz for internal routing connector
is not reqd, still we tried this. The external email with attachment of
16-18MB comes till our Bridgehead server from where a NDR gets generated and
the original mail is sent to the NDR mailbox which is on another server in
the same Org.
Below is the NDR that we get in the NDR mailbox:

Your message did not reach some or all of the intended recipients.

Subject: Monday Size Test
Sent: 20/07/2009 10:50

The following recipient(s) could not be reached:

Nair Nitin on 20/07/2009 10:56
This message is larger than the current system limit or the
recipient's mailbox is full. Create a shorter message body or remove
attachments and try sending it again.
<awss10341.globalinfra.net #5.2.3>

What we are not able to understand here is, the limit has been increased at
all possible points. Then what is the current system limit it is talking
about. We have tested this with various attachment but anything above 10MB is
not received in our mailbox. Any help in this regard will be really
appreciated!!