DNS Problem

[Ng King Wang]

Hi all,

My colleague and I have set up a Linux Redhat 8.0 (that is also our DNS and mail server) 2 weeks ago. We provide web and email hosting service for some customers.

Two clients told me that they could not send emails to the email account (dng@e-ascender.com) that is hosted by our email server.

The strange thing is that other clients can successfully send emails to the same email account (dng@e-ascender.com).

Any idea? Pls help.

Error message is as below:

-------------------------------------------

From: "Mail Delivery Subsystem"
To:
Sent: Sunday, August 24, 2003 1:38 PM
Subject: Returned mail: see transcript for details


The original message was received at Sun, 24 Aug 2003 13:38:27 +0800
from imsantv21 [127.0.0.1]

----- The following addresses had permanent fatal errors -----


----- Transcript of session follows -----
550 5.1.2 ... Host unknown (Name server:
es1.e-ascender.com.: host not found)

[Steven E. Protter]

This might be due to dns latency.

Believe it or not some ISP's don't keep up with DNS changes, or are very late in doing so.

At the affected customer site, try nslookup or dig and see if there is resolution.

At the customer site if its linux:

sendmail -v -d8 -d38 dng@e-ascender.com

type a line of text

.


You should be able to diagnose the problem with that.

SEP