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IP address initiating the connection

Printed From: LogSat Software
Category: Spam Filter ISP
Forum Name: Spam Filter ISP Support
Forum Description: General support for Spam Filter ISP
URL: https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=708
Printed Date: 05 February 2025 at 7:53am


Topic: IP address initiating the connection
Posted By: Guests
Subject: IP address initiating the connection
Date Posted: 29 May 2003 at 12:24pm

DNS blocklists:  Does SpamFilter check the "original initiating connection" ...or the last connection (the firewall address) forwarding the message to SpamFilter server? 

 

 




Replies:
Posted By: LogSat
Date Posted: 29 May 2003 at 5:24pm

It checks whatever IP is making the connection to the NIC card on the SpamFilter's server. This may or may not be the firewall's address. Most firewalls will allow you to "pass on" the external address connecting to the firewall down to the private interface, allowing the server SpamFilter is on to see the actual remote IP rather than the firewall's IP.

Roberto Franceschetti
LogSat Software



Posted By: Desperado
Date Posted: 31 May 2003 at 2:51am

Just to clarify ... when a remote mail server makes a connection to YOUR mail server on port 25 (or any other port for that matter) the only IP the local server sees is the inbound connections IP. A firewall and all the routers and switches in between are not making the connection to the server so they are effectivly not "seen" by the receiving server.  This has nothing to do with the SpamFilter software ... it has to do with the way a connection is made from machine to machine VIA TCP/IP. 

In the reverse direction, if you are doing NAT (network address translation) the remote server sees your NAT address, not the private address of your server.  If you were a Spammer, the IP on your NAT device (firewall or router) would be the IP that would eventually get on a blackhole list so in that case, ALL servers, inside your network would become blocked.

Dan Seligmann




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