mail server not able to send mail to hotmail

Hi guys,

I have a mail server behind a firewall in a dmz, the mail server seems to be fine and is not blacklisted, but the firewall is listed as being blacklisted, this seems to create a problem sending to hotmail addresses, no other addresses are affected by this only hotmail, can anyone shed why the mail server cannot send if the firewall is blacklisted to hotmail, but the mail server can send to everyone else rather than hotmail. i understand that hotmail use sender id and and other various technologies, but. Hotmail can send email to this domain in question, i cannot reply or send new emails. any help would be greatly appreciated.

Kind regards

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Because Hotmail checks to see if you blacklisted I would suppose.  Try checking your system with this.
Viral RathodConsultantCommented:
Try following steps,

1)Go to  note the ip address (This will give the public IP Address)
2) Please go to and check for blacklist (Enter the Public IP Address listed aboove)
Make sure your domain is not black listed
2) Go to and check the Inbound SMTP Email  Test Report
3) Also Telnet to from your server and send testmail using Telnet and check for the results
you will get the exact error

Hope this helps ,Letus know if you have any further query's.
Do a reverse lookup on the MX-records you are using.Is this the same IP as the MX-record you are using to sent mail? Most easy tool to check your MX and blacklist is

If a reverse lookup fails, the sending mail-server can (and by most spamfilters with reverse lookup will) be considered a  threat/spam and mails will be blocked.

Are you sure you can sent to other domains? And does a mail sent to hotmail generate an error-message?

Be aware thatmost spamfilters are configured not to notify the sender in case a reverse lookup fails. This to prevent spammers to find live addresses.
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derekbartelsAuthor Commented:
Hi Brian,

have used the tool and get an error on spf record. there is none

Hi Jamie,

If I'm reading your question correctly you want to know why the firewall is blacklisted and not the mail server?

I'm assuming in the DMZ setup your public edge firewall is NATting so to Hotmail the firewall is the mail server. So the black listing company that hotmail are using has the ip address of the firewall not the mail server (they wouldn't know it). The only way to fix it is get your ip removed from the blacklist (or change your public ip)

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derekbartelsAuthor Commented:
Thanks Scott,

yes that is what im looking for, i thought that was the case, I have asked Telstra to change our ip address as the blacklist does not seem to be removing the ip address.

It may not fix the problem. Some blacklisters will list your domain name as well. You'll have to find out which system is listing you and then find out how there system works.

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