sendmail

[Madhu Sudhan_1]

Friends,
I have a problem in mailing from my unix servers to a mail server which does reversename lookup while accepting mails. So Iam not able to send mails. How do I overcome this problem. Iam using SuSE Linux 7.0.

Thanks in advance.

[messias]

Hi Allen,

I think I know your problem.

You have configure your unix-servers
and your mail-server with the same domain.

If you sending a mail from the unix-server,
the machine looks in the local database for the
reciever (because it is his own domain).

You can fix this problem with two ways.

First, you can modify the domain-name from the unix-servers

or you configure a workaround

for example:
You use the domain "test.com"
Configure at your mailserver a subdomain with
the name "mailgate.test.com"
At the "mailgate.test.com" in the hosts with the mail-server ip-adress (in the unix-server)
If you sending mails from the unix-server
send they to user@mailgate.test.com.

Best regards
Nico

[Mark Fenton]

So is Niko on the right track? Or could you give us a little more info on what is and isn't working/your network setup.

(I'm confused by your description....)

[Madhu Sudhan_1]

Sorry about te incomplete information. Actual scene is,
I have my linux server in the lan and Iam able to send mails from it to hotmail.com, yahoo.com. But unable to sendmails to one particular domain.

Due to security reason I have hidden the actual domain names and usernames in the following transcript.
------------------

----- Transcript of session follows -----
... while talking to mail4.someother-dom.com.:
>>> MAIL From: SIZE=21
<<< 501 5.1.8 ... Domain of sender address guest@YAST_ASK does not exist
501 5.6.0 allen.solley@someother-dom.com... Data format error

--g0F9u3U25047.1011088563/oracledev.testdom.com
Content-Type: message/delivery-status

Reporting-MTA: dns; oracledev.testdom.com
Arrival-Date: Tue, 15 Jan 2002 01:56:02 -0800

Final-Recipient: RFC822; allen.solley@someother-dom.com
Action: failed
Status: 5.1.8
Diagnostic-Code: SMTP; 501 5.1.8 ... Domain of sender address guest@YAST_ASK does not exist
Last-Attempt-Date: Tue, 15 Jan 2002 01:56:03 -0800

--g0F9u3U25047.1011088563/oracledev.testdom.com
Content-Type: message/rfc822

Return-Path:
--------------

Thanks,

[Mark Fenton]

Allen,

I think I would look at the name resolution angle on the offended box (the mta that is rejecting this mail), and stick in an entry for the sending domain in /etc/hosts. For this to work, files has to be checked before DNS in nsswitch.conf.
~~~~~
hosts: files [NOTFOUND=continue ...] dns

If you do not have control over the offended box, that's another issue which would require some additional thought....

[Madhu Sudhan_1]

Mark, Thanks for the reply. I don't have control on the offended box. How do I over come this situation ?

Pls Help.

Regards,
Allen

[Maran · Accepted solution]

Make sure you have a PTR record on the external IP address of your mail server.

The easiest way to check is from an external dial-up account, using the ms-dos prompt type: ping -a xxx.xxx.xxx.xxx

x=external ip of your mail server

It should return with pinging mymailserver.mydomain.com xxx.xxx.xxx.xxx or something like that..the point is, it should be able to resolve the DNS name from the IP address.

I had this problem after we converted from 1 ISP to 2 different ISPs. (one for real business, one for internet and email) Our mail was going in/out on ISP2, however, ISP1 was hosting our external DNS.

The address of our mail server was an ISP2 address and ISP1 cannot create a PTR record for an IP they do not own. The solution I went with was to have ISP2 create a reverse PTR for my mail server address. Alternativly, you could have ISP2 assign authority for the IP block over to ISP1..

Or, just call whoever is in charge of your external DNS and tell them the problem, they can take care of it.. :)

Hope this helps.

Maran

[Penona Chan]

Wondering if this problem has been resolved.

If not, contact your ISP and like Maran suggested make sure they have entered the reverse PTR record. Also, is that IP range that your mailserver is allocated by them registered with RIPE.
If not, then their hostmaster will have to send off a reverse-arpa form to RIPE to register the /24 to them so that it allows reverse IP lookups.

[Rahadul kabir]

Hi Allen,
I have the exac same problem.
The original message was received at Thu, 18 Jul 2002 14:03:48 -0700
from admin@localhost

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

(reason: 501 5.1.8 ... Domain of sender address admin@raq4-denver.uslynx.com does not exist)

----- Transcript of session follows -----
... while talking to www.acm-elert.net.:
>>> MAIL From: SIZE=344
<<< 501 5.1.8 ... Domain of sender address admin@raq4-denver.uslynx.com does not exist
501 5.6.0 ... Data format error

[ Part 2: "Delivery Status" ]

Reporting-MTA: dns; raq4-denver.uslynx.com
Arrival-Date: Thu, 18 Jul 2002 14:03:48 -0700

Final-Recipient: RFC822; admin@www.acm-elert.net
Action: failed
Status: 5.1.8
Diagnostic-Code: SMTP; 501 5.1.8 ... Domain of sender address admin@raq4-denver.uslynx.com does not
exist
Last-Attempt-Date: Thu, 18 Jul 2002 14:03:48 -0700


please let me know how you resolved the problem. thanks so much