what if I am a hosting company and have a customer who has 100 users with Outlook 
Express behind a firewall. They compose and send messages using Outlook Express, and 
Outlook Express gives it to my mail server.

-----Original Message-----
From: Len Conrad [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, January 22, 2003 2:30 PM
To: [EMAIL PROTECTED]
Subject: Re[5]: [IMail Forum] what a pain!



>Um, Len? "Such behavior" as 100 users sending from behind the same NAT
>router  is  not  legit?

nope. They're effectively equivalent to DUL.  Their mail clients should be 
sending to their org's SMTP gateway where their highly qualified and 
professional mail admin would be able to track their behavior in the SMTP 
logs.  Their org's firewall people should block outbound port 25 access 
just like ISP's do.

They should not be sending to Internet MX's.

So, let's say they do send, are forced to send their mail to the org's SMTP 
gateway.   It's statistically infinitesimal when an single ip has 
legitimately to open 100 simultaneous connects to public MX.  Such behavior 
is self-incriminating.

Here's the STMPD connections stats to an IMGate box protecting 5000 
mailboxes, from 00:00 to 14:00 hours Tuesday:

Host/Domain Summary: Messages Received (top 30)
  msg cnt   bytes   host/domain
  -------- -------  -----------
     525    43163k  aol.com
     517     5896k  returns.groups.yahoo.com
     319     6052k  yahoo.com
     305     8430k  hotmail.com
     166     1758k  from=<>
     153     8088k  columbus.rr.com
     133     2367k  ebay.com
     127      970k  lyris.depoconnect.com
     118   442435   rootsweb.com
     115     2974k  newsletter.online.com
     108      536k  newmailbox.com
      99   473134   js615.com
      98     4148k  msn.com
      87     2130k  vds.com
      83     3988k  unsubscribe.myfamily.com
      83   408481   midrange.com
      82   296783   list.ipswitch.com
      78   341456   marketwatchmail.com
      71     1377k  earthlink.net
      68     2385k  juno.com
      66   322208   untinc.com
      63     1398k  ochsendorf.com
      61   169883   crochetpartners.org
      59      943k  ms1.lga2.nytimes.com
      59      555k  clearance.overstock.com
      58      805k  compuserve.com
      57   298678   4funnytaf.com

So all of  aol's connections of 500/14 hours = less that one 
connection/minute.

So how do you get from that to 100 simultaneous connections ever being legit?

or even 100 connections/hour?

can't get there from here.  :))

>Hmm...that's  happening at thousands of legit
>sites as we speak...

no, it isn't.

>guess we should shut 'em down, then. :)

yep, don't even blink, Just Do It.

All sending from behind their NATs to one MX SIMULTANEOUSLY, is 
certainly  not legit. And they are DUL, they should not be sending to MX's 
but to their org's SMTP server.

>Methinks  you're not answering Scott's question as presented.

Who care's what the question was, when one has all the answers??  :))

Len


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