Hello all

I am the exchange admin for our company currently I manage 2 exchange 2003 
sp2 backend servers, and one exchange 2003 sp2 front end server. Recently 
the help desk staff upgraded the office to 2007 sp1, and part of the upgrade 
was to configure all the outlook clients so they use rpc over https. There 
are roughly 600 clients on the network, so now i have 600 users talking to 
my exchange front end server first before they talk to the one of the back 
end servers. What if any performance issues can i expect from this 
configuration? i would think that having to talk to a front end server first 
and then, have the front end server have to proxy the request back to one of 
the back end servers would be more of a performance hit vs  talking directly 
the mailbox server using rpc

My experience is that Outlook 2003 will use TCP/IP when it is available and 
switch to RPC over HTTPS when necessary.  I don't know if Outlook 2007 
changes this behavior, though.  Are you seeing your Outlook 2007 always 
using RPC over HTTPS?  I'm not sure why you'd want to do that in preference, 
since this method only really benefits you when users are outside your 
firewall.  Are you sure you're not confusing RPC over HTTPS with cached 
mode?  They're two different things although often used together.
-- 
Ed Crowley MVP
"There are seldom good technological solutions to behavioral problems."
.

"skip"  wrote in message 
news:50529ED6-D65C-4DBD-A1FD-83A04BDD7B6E@microsoft.com...
> Hello all
>
> I am the exchange admin for our company currently I manage 2 exchange 2003 
> sp2 backend servers, and one exchange 2003 sp2 front end server. Recently 
> the help desk staff upgraded the office to 2007 sp1, and part of the 
> upgrade was to configure all the outlook clients so they use rpc over 
> https. There are roughly 600 clients on the network, so now i have 600 
> users talking to my exchange front end server first before they talk to 
> the one of the back end servers. What if any performance issues can i 
> expect from this configuration? i would think that having to talk to a 
> front end server first and then, have the front end server have to proxy 
> the request back to one of the back end servers would be more of a 
> performance hit vs  talking directly the mailbox server using rpc
>

Hi Ed 

Thanks for the reply, but i think you may be misunderstanding me. I am 
running a single ex2003 spo2 front end server, and two ex 2003 sp2 backend 
servers. All clients are running outlook 2007 sp1, and recently all clients 
have been configured for rpc over https. I thought that if you configured the 
outlook client for rpc over https, then the client would always talk to front 
end server where the proxy vs is located, are you suggesting that the outlook 
client can switch back to mapi/rpc if the front end server was not available?

I guess i dont understand why anyone would configure all the internal 
clients for rpc over https, i would think Microsoft would  not recomend this 
setup. I see the logic if the client is exteranl to the network, but this 
change doenst make much sence if the clients are on the same network as the 
exchange servers. I would think with encryption and decryption that has to go 
on with the rpc over https connection, all the proxing to the back end 
exchange servers, and the overhead of client and front end sever having to 
setup a https tunnel that contains rpc and mapi traffic, would all be reason 
why you wouldnt want to make rpc over https the primary way clients talk to 
the exhcange servers?

Many thanks in advance

"Ed Crowley [MVP]" wrote:

> My experience is that Outlook 2003 will use TCP/IP when it is available and 
> switch to RPC over HTTPS when necessary.  I don't know if Outlook 2007 
> changes this behavior, though.  Are you seeing your Outlook 2007 always 
> using RPC over HTTPS?  I'm not sure why you'd want to do that in preference, 
> since this method only really benefits you when users are outside your 
> firewall.  Are you sure you're not confusing RPC over HTTPS with cached 
> mode?  They're two different things although often used together.
> -- 
> Ed Crowley MVP
> "There are seldom good technological solutions to behavioral problems."
> ..
> 
> "skip"  wrote in message 
> news:50529ED6-D65C-4DBD-A1FD-83A04BDD7B6E@microsoft.com...
> > Hello all
> >
> > I am the exchange admin for our company currently I manage 2 exchange 2003 
> > sp2 backend servers, and one exchange 2003 sp2 front end server. Recently 
> > the help desk staff upgraded the office to 2007 sp1, and part of the 
> > upgrade was to configure all the outlook clients so they use rpc over 
> > https. There are roughly 600 clients on the network, so now i have 600 
> > users talking to my exchange front end server first before they talk to 
> > the one of the back end servers. What if any performance issues can i 
> > expect from this configuration? i would think that having to talk to a 
> > front end server first and then, have the front end server have to proxy 
> > the request back to one of the back end servers would be more of a 
> > performance hit vs  talking directly the mailbox server using rpc
> > 
> 
> 
>

Yes all clinets are in cached exchange mode, and are configured for rpc over 
https

"Ed Crowley [MVP]" wrote:

> My experience is that Outlook 2003 will use TCP/IP when it is available and 
> switch to RPC over HTTPS when necessary.  I don't know if Outlook 2007 
> changes this behavior, though.  Are you seeing your Outlook 2007 always 
> using RPC over HTTPS?  I'm not sure why you'd want to do that in preference, 
> since this method only really benefits you when users are outside your 
> firewall.  Are you sure you're not confusing RPC over HTTPS with cached 
> mode?  They're two different things although often used together.
> -- 
> Ed Crowley MVP
> "There are seldom good technological solutions to behavioral problems."
> ..
> 
> "skip"  wrote in message 
> news:50529ED6-D65C-4DBD-A1FD-83A04BDD7B6E@microsoft.com...
> > Hello all
> >
> > I am the exchange admin for our company currently I manage 2 exchange 2003 
> > sp2 backend servers, and one exchange 2003 sp2 front end server. Recently 
> > the help desk staff upgraded the office to 2007 sp1, and part of the 
> > upgrade was to configure all the outlook clients so they use rpc over 
> > https. There are roughly 600 clients on the network, so now i have 600 
> > users talking to my exchange front end server first before they talk to 
> > the one of the back end servers. What if any performance issues can i 
> > expect from this configuration? i would think that having to talk to a 
> > front end server first and then, have the front end server have to proxy 
> > the request back to one of the back end servers would be more of a 
> > performance hit vs  talking directly the mailbox server using rpc
> > 
> 
> 
>

On Tue, 8 Jul 2008 07:13:01 -0700, skip
 wrote:

>Thanks for the reply, but i think you may be misunderstanding me. I am 
>running a single ex2003 spo2 front end server, and two ex 2003 sp2 backend 
>servers. All clients are running outlook 2007 sp1, and recently all clients 
>have been configured for rpc over https. I thought that if you configured the 
>outlook client for rpc over https, then the client would always talk to front 
>end server where the proxy vs is located, are you suggesting that the outlook 
>client can switch back to mapi/rpc if the front end server was not available?

There are two checkboxes on the "Exchange proxy settings". One is "On
fast networks . . ." and the other is "on slow networks . . .". The
typical configuration is to check only the "On slow networks . . ."
box. When doen that way the Outlook client will use RPC-Over-HTTPS
only when it cannot connect directly to the mailbox server.

And, yes, if the Outlook client is using RPC-Over-HTTPS and a TCP/IP
connection becomes available then Outlook will switch to the TCP/IP
(i.e. high-speed) connection -- assuming the connection isn't a real
pig.

>I guess i dont understand why anyone would configure all the internal 
>clients for rpc over https, i would think Microsoft would  not recomend this 
>setup. 

They don't

>I see the logic if the client is exteranl to the network, but this 
>change doenst make much sence if the clients are on the same network as the 
>exchange servers. 

You're correct. It doesn't make sense. That's why Ed's questioning why
you think your LAN-connected Outlook clients are using your Front-End
servers.

>I would think with encryption and decryption that has to go 
>on with the rpc over https connection, all the proxing to the back end 
>exchange servers, and the overhead of client and front end sever having to 
>setup a https tunnel that contains rpc and mapi traffic, would all be reason 
>why you wouldnt want to make rpc over https the primary way clients talk to 
>the exhcange servers?

We're all in agreement on those points.
---
Rich Matheisen
MCSE+I, Exchange MVP

On Tue, 8 Jul 2008 07:21:01 -0700, skip
 wrote:

>Yes all clinets are in cached exchange mode, and are configured for rpc over 
>https

Are they configured to use RPC-Over-HTTPS for both fast and slow
networks? If they are, they're in an unusual configuration. Usually
you'd only check the "On slow networks . . ." checkbox.
---
Rich Matheisen
MCSE+I, Exchange MVP

Ok i understand now, and yes the only box that is checked is "on slow 
networks" so what would happen if the front end exchange server was 
unavailable, would the Outlook client just make a tcp/ip connection directly 
to the mailbox server and not care that the front end server was unavailable?

Thanks

"Rich Matheisen [MVP]" wrote:

> On Tue, 8 Jul 2008 07:21:01 -0700, skip
>  wrote:
> 
> >Yes all clinets are in cached exchange mode, and are configured for rpc over 
> >https
> 
> Are they configured to use RPC-Over-HTTPS for both fast and slow
> networks? If they are, they're in an unusual configuration. Usually
> you'd only check the "On slow networks . . ." checkbox.
> ---
> Rich Matheisen
> MCSE+I, Exchange MVP
>

> Ok i understand now, and yes the only box that is checked is "on slow
> networks" so what would happen if the front end exchange server was
> unavailable, would the Outlook client just make a tcp/ip connection 
> directly
> to the mailbox server and not care that the front end server was 
> unavailable?


Yes,

Also Outlook 2007 elevates NPP (Non Paged Pool) on Exchange 2003 Backends. 
For 600 users though I don't see this being an issue.

Oliver

My experience is that regardless of how you set those checkboxes Outlook 
will try a TCP connection in preference to an HTTPS one.  Maybe yours is 
different, but I've tried forcing HTTPS (for testing of course), and my 
Outlook 2003 will always connect using TCP if it can.
-- 
Ed Crowley MVP
"There are seldom good technological solutions to behavioral problems."
.

"Rich Matheisen [MVP]"  wrote in message 
news:9378741dhcce4o9fb0lrvo14ru4c083epu@4ax.com...
> On Tue, 8 Jul 2008 07:13:01 -0700, skip
>  wrote:
>
>>Thanks for the reply, but i think you may be misunderstanding me. I am
>>running a single ex2003 spo2 front end server, and two ex 2003 sp2 backend
>>servers. All clients are running outlook 2007 sp1, and recently all 
>>clients
>>have been configured for rpc over https. I thought that if you configured 
>>the
>>outlook client for rpc over https, then the client would always talk to 
>>front
>>end server where the proxy vs is located, are you suggesting that the 
>>outlook
>>client can switch back to mapi/rpc if the front end server was not 
>>available?
>
> There are two checkboxes on the "Exchange proxy settings". One is "On
> fast networks . . ." and the other is "on slow networks . . .". The
> typical configuration is to check only the "On slow networks . . ."
> box. When doen that way the Outlook client will use RPC-Over-HTTPS
> only when it cannot connect directly to the mailbox server.
>
> And, yes, if the Outlook client is using RPC-Over-HTTPS and a TCP/IP
> connection becomes available then Outlook will switch to the TCP/IP
> (i.e. high-speed) connection -- assuming the connection isn't a real
> pig.
>
>>I guess i dont understand why anyone would configure all the internal
>>clients for rpc over https, i would think Microsoft would  not recomend 
>>this
>>setup.
>
> They don't
>
>>I see the logic if the client is exteranl to the network, but this
>>change doenst make much sence if the clients are on the same network as 
>>the
>>exchange servers.
>
> You're correct. It doesn't make sense. That's why Ed's questioning why
> you think your LAN-connected Outlook clients are using your Front-End
> servers.
>
>>I would think with encryption and decryption that has to go
>>on with the rpc over https connection, all the proxing to the back end
>>exchange servers, and the overhead of client and front end sever having to
>>setup a https tunnel that contains rpc and mapi traffic, would all be 
>>reason
>>why you wouldnt want to make rpc over https the primary way clients talk 
>>to
>>the exhcange servers?
>
> We're all in agreement on those points.
> ---
> Rich Matheisen
> MCSE+I, Exchange MVP

On Wed, 9 Jul 2008 09:53:09 -0400, "Ed Crowley [MVP]"
 wrote:

>My experience is that regardless of how you set those checkboxes Outlook 
>will try a TCP connection in preference to an HTTPS one.  

That's true for the directory services. The mailbox and public folders
will use HTTPS.

>Maybe yours is 
>different, but I've tried forcing HTTPS (for testing of course), and my 
>Outlook 2003 will always connect using TCP if it can.

Check again and see if it the directory service that's using TCP/IP.
---
Rich Matheisen
MCSE+I, Exchange MVP

On Tue, 8 Jul 2008 19:50:01 -0700, skip
 wrote:

>Ok i understand now, and yes the only box that is checked is "on slow 
>networks" so what would happen if the front end exchange server was 
>unavailable, would the Outlook client just make a tcp/ip connection directly 
>to the mailbox server and not care that the front end server was unavailable?

Assuming the Outlook client is on a LAN the FE server won't be used
for anything -- unless the client can't connect to the BE server for
some reason. That inability to connect will force a switch from TCP/IP
to HTTPS and the Outlook client will (try to) connect to the FE
server.

This changes a bit for Exchange 2007 because the Outlook 2007 client
will try contacting the CAS for Autodiscover services and possibly for
the Offline Addres Book. In the absence of public folders, the Outlook
client will use the CAS to get information from the calendars of
mailboxes instead of from the F/B folder.
---
Rich Matheisen
MCSE+I, Exchange MVP

Here is something worth checking.
When using RPC over HTTPS directory lookup performance can be dramatically
improved by making a change to the Internet Explorer settings on the Outlook
client machine. (Yes, this is no joke.)

Open Internet Explorer, under, Tools, Internet Options, connections, LAN
settings. Make sure the box for "Automatically detect settings" is
UNCHECKED.

Test with Outlook /rpcdiag from the command line to see the difference in
performance.

I hope this helps.
Dana

"Rich Matheisen [MVP]"  wrote in message
news:0r0a74haiiioqtvqv8l8ihe6igke3tlb7f@4ax.com...
> On Wed, 9 Jul 2008 09:53:09 -0400, "Ed Crowley [MVP]"
>  wrote:
>
> >My experience is that regardless of how you set those checkboxes Outlook
> >will try a TCP connection in preference to an HTTPS one.
>
> That's true for the directory services. The mailbox and public folders
> will use HTTPS.
>
> >Maybe yours is
> >different, but I've tried forcing HTTPS (for testing of course), and my
> >Outlook 2003 will always connect using TCP if it can.
>
> Check again and see if it the directory service that's using TCP/IP.
> ---
> Rich Matheisen
> MCSE+I, Exchange MVP