Solved

Cant send mail to one domain

Posted on 2009-06-30
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1,702 Views
Last Modified: 2012-05-07
dear all,

I'm having this problem when i'm trying to send an email to this domain and the NDR reply that I get is:

Your message did not reach some or all of the intended recipients. May I know the cause of this error?


      Subject:      TEST
      Sent:      01/07/2009 11:39 AM

The following recipient(s) could not be reached:

      yyy@tungshin.com.my on 01/07/2009 11:25 AM
            The e-mail system was unable to deliver the message, but did not report a specific reason.  Check the address and try again.  If it still fails, contact your system administrator.
            < mail.xxx.com.my #5.0.0 smtp; 550-Callback setup failed while verifying <xxx@xxx.com.my>    550-(result of an earlier callout reused). 550-The initial connection, or a HELO or MAIL FROM:<>    command was 550-rejected. Refusing MAIL FROM:<> does not help fight spam, disregards 550-RFC    requirements, and stops you from receiving standard bounce 550-messages. This host does not    accept mail from domains whose servers 550-refuse bounces. 550 Sender verify failed>
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Question by:otyew
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18 Comments
 
LVL 23

Assisted Solution

by:debuggerau
debuggerau earned 50 total points
ID: 24751682
yes, it looks like they are doing sender verification..

Previous discussion here:
http://www.experts-exchange.com/Networking/Email_Groupware/Exchange_Server/Q_21128857.html

You may want to setup another send connector for them.
Thank Mestha for this link..
http://www.amset.info/exchange/smtp-connector.asp

0
 

Author Comment

by:otyew
ID: 24751803
the problem is that after emails are out of exchange, it will pass through mailsweeper before it is being sent. so i am not sure if this is applicable to exchange or not. btw is this our issues or the other parties issue?
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LVL 23

Expert Comment

by:debuggerau
ID: 24751915
well I suppose it could be deemed your problem since you may not have the correct PTR records in DNS.
Does your mail server have a corresponding DNS entry they can lookup?
http://blogs.technet.com/industry_insiders/pages/sender-verify-failed-with-incorrect-reverse-dns-record.aspx
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LVL 24

Assisted Solution

by:ryder0707
ryder0707 earned 30 total points
ID: 24751980
Many SMTP servers in internet implement reverse dns lookup for ip address to prevent spam
This is to test the ip address is registered/belong to the particular domain since a hacker can spoof any ip with different domain name to send email
you can manually test this at http://www.mxtoolbox.com under diagnostic
if your ip failed this reverse lookup, you need to work with your ISP to create one for u
see example below from a random domain name, perhaps this could be the problem
rdns.jpg
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Author Comment

by:otyew
ID: 24752123
tested it before and why only this url is having problems but not others as well? we are dealing with a lot of external users from normal home users till corporate clients but only this are having problems.
untitled.JPG
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Author Comment

by:otyew
ID: 24752142
also this happens last week and when i run a check on our mailserver ip, it was in blacklist. it was fine after it was removed but now, it doesnt seems to be the problem.
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LVL 24

Expert Comment

by:ryder0707
ID: 24752207
hmmm not really sure, perhaps that particular smtp server is doing extra smtp verification as i can see "command is rejected"
what i'll do is to forward or relay emails for that particular domain to isp smtp server
if you are using exchange, just create a smtp connector for that particular domain
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LVL 24

Expert Comment

by:ryder0707
ID: 24752214
in other words, all problematic smtp domain to be forwarded to isp smtp server for relaying
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LVL 40

Accepted Solution

by:
Subsun earned 120 total points
ID: 24752795
Reverse DNS lookup, this is one of the Anti-spam techniques. This method is time-consuming and it is rarely used. The receiving server performs a reverse DNS lookup on the IP address of the incoming connection and checks if there is a valid domain name associated to it.

But some administrators follow this technique, for example AOL.
http://postmaster.info.aol.com/errors/421dnsnr.html
http://postmaster.info.aol.com/info/rdns.html

You may check the part "Why should I worry about reverse DNS (rDNS)?" on following article.
http://www.spamhaus.org/faq/answers.lasso?section=ISP%20Spam%20Issues

If you are on a static IP address, please call your ISP or DNS provider and ask them to establish a reverse DNS record for your IP address, reflecting your correct domain name if not advise remote email admin to white-list your outbound IP or create a pass through for your outbound IP.
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Author Comment

by:otyew
ID: 24759897
this is on a fixed ip btw, what should we do about this? so this means that the other side is doing a reverse dns checking and since we do not have it, it rejects our mail?
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Expert Comment

by:debuggerau
ID: 24759940
you got it in one..
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LVL 40

Expert Comment

by:Subsun
ID: 24760756
Yes...To resolve this you need to establish a reverse DNS record for your outbound IP address or contact the remote email admin to check the alternative (white listing or pass through IP)
0
 

Author Comment

by:otyew
ID: 24761247
i guess i can send it now. it is because of the blacklist.....but i think the reverse dns plays a part of it. the i am not sure why it get blacklisted daily. hope to get some comment before i close this? btw, it was CBL who blacklisted us, only this one.

ps-it is hard to give u guys the points everyone will get some. i will raise my points and then will choose the best answers.  thanks guys
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LVL 40

Expert Comment

by:Subsun
ID: 24761301
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Author Comment

by:otyew
ID: 24761879
ok, the problem is this. before the mail goes out, it will be passing though a spam filter (mimesweeper). is the configuration should be done through exchange or this spam filters?
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LVL 40

Expert Comment

by:Subsun
ID: 24761952
You need to check all your exchange servers and make sure that it is not open relay. Also run ExBPA to verify the configurations.

Is mimesweeper scanning your outgoing emails?
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Author Comment

by:otyew
ID: 24770750
yes, mailsweeper is scanning. since exchange mail will go through the mailsweeper, i guess it is the mailsweeper that needs to be configured.
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Expert Comment

by:Subsun
ID: 24770837
Yes you can fine tune the mail sweeper to block the outgoing/incoming SPAM but it is also important that your exchange servers should not be open relay because if your exchange is an open relay any Trojan/Virus or anyone could Send Spam Through your server which may cause trouble for you as no SAPM filtering system is capable of blocking 100% SPAM, Always prevention is better than cure.
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