421 4.4.2 connection dropped due to SocketError

I have problmes to send mails, exchange sent me tihs error: 451 4.4.0 primary target iIPaddress respondend with "421 4.4.2 conection dropped due to socketerror
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

How many exchange servers do you have,..?
mails are suck in which queue..?
Also check the ip blacklist once.

Also check this once
ATIOSAAuthor Commented:
Thanks to both, Actually I have only one server, I don't understand about the queue.. I checked black list and everythingis ok.
Ultimate Tool Kit for Technology Solution Provider

Broken down into practical pointers and step-by-step instructions, the IT Service Excellence Tool Kit delivers expert advice for technology solution providers. Get your free copy now.

ATIOSAAuthor Commented:
Hi, i tested creating the DWORD value in the registry but the problem not solve. any idea?
Under Server Configuration right click on the server and select properties, under External DNS lookups, add your ISP DNS servers in here.

Then under Organisation Configuration > Hub Transport, check the properties of your internet send connector under Network check the box to use External DNS lookup settings.

Restart the Microsoft Exchange Transport service
Issue can also be caused by your firewall
Have you kept any firewall between both site WAN connectivity, Are you able to telent other site Exchange Server at port 25 and can send test mail thru SMTP command ?? . Also try to restart HUB transport servive on remote HUB server and check the status.

Please send test mail thru SMTP comand and share result.

Use Telnet to Test SMTP Communication:
Also please check you Ip is not listed on the Black list too

ATIOSAAuthor Commented:
Hi Sumit, I test the first steps you mention but nothing change. Here is the result for mail thru SMTP command

220 mail.atio.com.mx ESMTP (302e03eed096096c5f4feb752280b0b1)
helo hotmail.com
250 mail.atio.com.mx Hello hotmail.com [], pleased to meet you
mail from:xx@hotmail.com
250 Ok
rcpt to: xx@atio.com.mx
554 Service unavailable; Client host [hotmail.com] blocked using Barracuda Reputation; http://www.barracudanetworks.com/reputation/?r=1&ip=

I'm not in blacklist.
check setting on barracuda, i think its causing this issue  
ATIOSAAuthor Commented:
I talked with my ISP and apparently is a problem with a PTR register in DNS SERVER... I hope to found a solution.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
any update on this issue
Similar problem.

Exchange 2010 on Win SBS 2011 server.

I have 2 outside email domains getting this error.  All other email flows thru.

SMTP via telnet works.

Interesting that both smtpsend log shows at the end, before retrying the connection
2013-03-14T00:03:01.558Z,Default to Internet,08CFD871781A7418,0,,,*,,attempting to connect
2013-03-14T00:03:01.558Z,Default to Internet,08CFD871781A7418,1,,,+,,

IP address, in the last line, is different then the original  EHLO session ip addresss- clue?
ATIOSAAuthor Commented:
At the end, there was a problem with DNS resolutions.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.