changing the number of allowed connections

Posted on 2006-05-15
Last Modified: 2013-12-17
Hi there,

I have a web server that is set up to email me error notices of PHP errors via a script that makes an SMTP connection to localhost. This works fine, but the other day I inadvertently wrote a script with an error in a for loop that got thrown over and over, generating many email reports in a very short time. Some of them got through to my remote email, but the ones that happened in the later iterations of the loop never came. Checking the root email account, I found many delivery failure notices:

From: Mail Delivery Subsystem <>
Subject: Postmaster notify: see transcript for details
   1     Shown     11 lines  Text
   2     Shown    405 bytes  Message, "Delivery Status"
   3     Shown    2.9 KB     Message, "Returned mail: see transcript for details"
   3.1   Shown     12 lines  Text
   3.2   Shown    405 bytes  Message, "Delivery Status"
   3.3   Shown      1 KB     Message, " Error Report"
   3.3.1 Shown     10 lines  Text

The original message was received at Sun, 14 May 2006 22:54:55 -0400
from localhost
with id k4F2st6C015139

   ----- The following addresses had permanent fatal errors -----
    (reason: 550 Too many SMTP connections from xx.xx.xx.xx!) <----my IP (not localhost or 127.0.01, if that matters)
    (expanded from: <>)

   ----- Transcript of session follows -----
554 5.0.0 Service unavailable

    [ Part 2: "Delivery Status" ]

Reporting-MTA: dns;
Received-From-MTA: DNS; localhost.localdomain
Arrival-Date: Sun, 14 May 2006 22:54:55 -0400

Final-Recipient: RFC822;
X-Actual-Recipient: RFC822;
Action: failed
Status: 5.5.0
Diagnostic-Code: SMTP; 550 Too many SMTP connections from xx.xx.xx.xx!    <----my IP (not localhost or 127.0.01, if that matters)
Last-Attempt-Date: Sun, 14 May 2006 22:54:55 -0400

[ Part 3.3: "Included Message" ]

<original error report email>

is there a way to increase the number of concurrent SMTP connections a particular user can make from localhost so that my error messages will get through? Especially as site traffic grows, I want to be sure I dont miss any. In addition, well need to send news letters out to members using the same base email software, so I need to be sure they don't get lost.

Thanks in advance for the help!
Question by:nicholassolutions
    LVL 15

    Author Comment

    PS: If you need to see parts of my config files just ask. Sendmail is really not my area of expertise, so you'l' have to bear with me.
    LVL 5

    Accepted Solution

    can you try following on

    # maximum number of new connections per second
    #O ConnectionRateThrottle=0

    after change restart the sendmail
    LVL 15

    Author Comment

    stupidly, I've now realized that it was the receiving server that had limited the connections, and not my own. Thanks for pointing out this option though -- it taught me something and I found some other useful info while researching it further.

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