My ip blacklisted but using ips smtp

I'm running Exchange on a Dynamic ip address at my cable provider. I've read that I have to use my ISPs smtp server. I've been doing so for as long as I can remember, but the problem i'm having now is that my own external ip is listed in RBL. I thnink because mailheaders contain this ip I still get blocked by other mailservers.

Is there any way to work around this problem? Because I have to delist my ip everytim which is taking hours.
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If you send through your smarthost it doesn't matter if your own dynamic IP is blacklisted.

You can't send using DNS on a dynamic IP.

LufaaAuthor Commented:
This is how I configured my exchange.
see attachement
and this is what I get when mail is bounced.

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

Subject: test
Sent: 4/26/2010 8:10 PM

The following recipient(s) cannot be reached:

'' on 4/26/2010 8:10 PM
The e-mail account does not exist at the organization this message was sent to. Check the e-mail address, or contact the recipient directly to find out the correct address.
< #5.1.1 smtp;550 5.1.1 <> recipient rejected is in RBL>

by the way: where in exchange can I change the domain being send as which i written in bold letters, because this domain stopped working and now i have antoher primary domain.

It appears your smarthost is blocked (but this may not be the IP they use for outbound mail of course, so might be a red herring): -

Is this the IP in the bounce? The bounce is a little odd because it says the recipient doesn't exist (which is a normal 5.1.1) and then speaks of a RBL.

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As for chaning the primary email address, this is done using recipient policies:

LufaaAuthor Commented:
no the / is not my ip of the internetconnection. That is my ISPs smtp / ipaddress.
My own ipaddress is in the bounce.
Can you send me a test email at and I'll check it is going through your smarthost as last hop,

LufaaAuthor Commented:
here is the bounce
I'd speak with your smarthost providers because it looks to me like your smarthost is blocking your server because it is on a blacklist.

You should make sure you aren't sending out SPAM from your IP by scanning all PC's in your org for any SMTP bots (use antivirus / antimalware software for this).


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LufaaAuthor Commented:
Is it possible to use another smarthost? I'd like to use Vodafone smtp as smarthost but this needs smtp authentication (because I don't have Vodafone internet) but can I configure this in Exchange 2003?
LufaaAuthor Commented:
I used to have a program that monitors outgoing email over port 25, but can't find it anywhere. Do you now of such a program so I can install it on my workstation and see if this is the one that's sending out spam over port 25.
Other little thing. There are users who use my exchange server via rpc over http and they are not even in the neighbourhood. Can there pc's if infected with smtp bots also use my server to send out spam our is this only possible via vpn-connection to my sbs2003 server? And if logged on via RDP?
Yes, if you have a username/password combo.

SMTP Connector --> Advanced --> Outbound security.

No, BOTS won't use your server to relay, they will just go out directly.

Any good network monitoring software will help on a per PC basis - wireshark / network monitor 3.3 etc

Best of all, block port 25 outbound for all devices except the exchange server on a firewall device.

LufaaAuthor Commented:
Wireshark was exaclty the one I was looking for... Thanks a lot.
If you can solve this las riddle for me then you earn all the points... How the "bleep" do I block outgoing port 25 only for my Exchange on my Linksys router? As far as I can see I can only route my incoming port 25 to my server....
It depends on the firewall, sometimes you don't have this feature. A lot of small home and small office devices will only allow static NAT mappings such as what you are seeing and don't provide for blocking outbound traffic.

Next best thing to do is to make sure all your workstations are scanned and/or block port 25 using IPSec and GPO but it gets a bit involved.

LufaaAuthor Commented:
It helped me with getting to know the smarthost function and firewall with port 25
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