spamblocker checking sender ip addresses

Chrysalis

Verified User
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Aug 25, 2004
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uk
We have had an issue where a user's isp has their entire range blacklisted, he is logging into the smtp server to send an email and spamblocker is blocking the email because his ip is on a blacklist. The issue I see here is the sender isnt a smtp server he is simply logging into the smtp server to send email. Given also that some blacklists add all dynamic ip ranges as well is it possible to have spamblocker not check senders ip addresses? maybe something like if the from domain is a local domain hosted on the server spamblocker is bypassed.

For now we have whitelisted the ip address.
 

nobaloney

NoBaloney Internet Svcs - In Memoriam †
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Jun 16, 2003
Messages
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California
Your user can resolve the issue one or two ways; he can use port 587 on your server to send mail (which eliminates checks) or he can use his ISP's mail server.

Your idea:
if the from domain is a local domain hosted on the server spamblocker is bypassed.
opens up your server to being used as a spam server by anyone spoofing your user's domain. We see this problem all the time; generally it's only a short time before you whitelist your user's domain name and the spam starts flowing through your server. Only days.

Jeff
 

Chrysalis

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Joined
Aug 25, 2004
Messages
1,584
Location
uk
yeah I was curious about the spoofing issue, thanks for the information concerning 587 I was unaware it bypasses it.
 
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