after logon in owa, see internal ip on the url ???

[framfram]

Hi all,
I have an exchange server on the lan and I'm currently testing https owa. The config is : I have local DNS and forwarders are set to provider dns. On the firewall there is the mail server ip public address is nat to the internal ip address. The problems are :

1) from inside when I type webmail.domain.com, after succeeded in logon on https owa, I see on the URL our internal IP address :when does it switch to our internal IP ?

2) from outside when typing webmail.domain.com, I can get to the logon page but I cannot connect to my mailbox : what could it be ? Is there any correlation with the switch to our internal IP when logon from inside ?

Please HELP !!! Thanks ...

 

[framfram]

Additional question :
Sorry for the 1rst problem, it'is not when but why does it switch to our internal IP ?
And for the 2nd problem : from inside, after succeeded in logon and because that switchs to the internal ip, is that because our internal ip is not known from outside, then from outside, I cannot logon ? Might it be more a resolution pb or authentication pb ?

Thanks ...

 

[xmsre]

1. have you set your host headers correctly?

http://support.microsoft.com/kb/287726/en-us

2. do you have a cname entry in your internal dns for webmail?

 

[framfram]

1) following the url, I need to add IP address and FQDN on the exchange virtual server but I cannot add any setting on the one installed by default. Is that normal ?
2) I add a cname entry in my internal dns but still I cannot access to my mailbox
By typing the url

https://webmail.domain.com

-from outside I get the error HTTP 403 -refused Internet Explorer
-from inside I can logon and I still get the url that returm my internal ip address

Any other ideas ? Thanks