Solved

XXXX Command in SMTP?  What does it mean?

Posted on 2004-04-19
2
326 Views
Last Modified: 2010-05-02
I'm currently building an app to intercept SPAM mail via an SMTP relay.  The only problem I've got is that some mail servers send a XXXX command prior to sending their HELO.  I've looked high and low to find out what the reason for the XXXX is, and haven't found anything anywhere.  My mail server just generates an error when it gets it.  Here's an example of the handshake just prior to an E-Mail being sent:

>  220 mail.(ourserver).com ESMTP Server (Microsoft Exchange Internet Mail Service 5.5.2655.55) ready[CR][LF]
>> XXXX grebe.mail.pas.earthlink.net[CR][LF]
> 500 Command not recognized.[CR][LF]
>> HELO grebe.mail.pas.earthlink.net[CR][LF]
>  250 OK[CR][LF]
>> MAIL FROM:<blah@earthlink.net>[CR][LF]
>  250 OK - mail from <blah@earthlink.net>[CR][LF]

That first XXXX command sent is what's losing me.  And it's not just earthlink that does it.  Like I said, I've searched high and low for something explaining it with no luck.  Best I'm able to guess is that for some reason maybe they WANT to generate an error response on the server for some reason.  Anyone with the answer gets 500 points.  (And no theories, please.  I need to know WHY they do this.)

-Javin
0
Comment
Question by:Javin007
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 17

Accepted Solution

by:
zzzzzooc earned 500 total points
ID: 10862577
>> XXXX grebe.mail.pas.earthlink.net[CR][LF]
>> 500 Command not recognized.[CR][LF]

Cisco PIX Firewalls filter SMTP content. If you use non-basic commands, the real command will be replaced with "XXXX" and then it'll be followed by "500 Command not recognized".
0
 
LVL 4

Author Comment

by:Javin007
ID: 10863322
Aha.  So this is likely an EHLO command or some such.  Makes sense.  We do have a Cisco Pix.

Thanks!

-Javin
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Most everyone who has done any programming in VB6 knows that you can do something in code like Debug.Print MyVar and that when the program runs from the IDE, the value of MyVar will be displayed in the Immediate Window. Less well known is Debug.Asse…
This article describes some techniques which will make your VBA or Visual Basic Classic code easier to understand and maintain, whether by you, your replacement, or another Experts-Exchange expert.
Get people started with the process of using Access VBA to control Outlook using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Microsoft Outlook. Using automation, an Access applic…
Get people started with the process of using Access VBA to control Excel using automation, Microsoft Access can control other applications. An example is the ability to programmatically talk to Excel. Using automation, an Access application can laun…

690 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question