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lworxtech's profile

New Contributor

 • 

12 Messages

Thu, Feb 27, 2014 10:00 AM

Outgoing blocked - 76.96.107.73 is listed on rbl.securence.com

Hello,

Since yesterday afternoon our company has been unable to send emails to certain domains. Our domain is "lauchlanworks.com" and is hosted through your Exchange mail server(s). So far it has become impossible to send to the following domains: siriuscom.com, mjm.com & accunetsolutions.com. We have a number of users who need to be able to contact these domains (and any others which are disallowing connections from your server) as soon as possible. We have run into this in the past but only when using the POP server - in this case, each of the affected accounts are Exchange. Please let me know what can be done about this and how soon. Thanks!

Here are a couple of the rejection notices:

 

@sirius.com

 

Reporting-MTA: dns; omta03.potomac.co.businessclass.comcast.net [76.96.107.73]

Received-From-MTA: dns; CH1HUB02.CH1.COMCAST.NET [172.28.148.147]

Arrival-Date: Thu, 27 Feb 2014 17:29:21 +0000

 

Final-recipient: rfc822; XXXXXX@siriuscom.com

Action: failed

Status: 5.1.1

Diagnostic-Code: smtp; 550 Unable to add XXXXXX@siriuscom.com because host 76.96.107.73 is listed on rbl.securence.com

Last-attempt-Date: Thu, 27 Feb 2014 17:29:21 +0000

 

@mjm.com

 

Reporting-MTA: dns; omta03.potomac.co.businessclass.comcast.net [76.96.107.73]

Received-From-MTA: dns; CH1HUB02.CH1.COMCAST.NET [172.28.148.147]

Arrival-Date: Thu, 27 Feb 2014 17:28:17 +0000

 

Final-recipient: rfc822; XXXXXX@mjm.com

Action: failed

Status: 5.1.1

Diagnostic-Code: smtp;  550 Connection refused

Last-attempt-Date: Thu, 27 Feb 2014 17:28:17 +0000

Responses

Accepted Solution

New Contributor

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12 Messages

7 y ago

1. Both, depending on the location / situation, though primarily through Outlook 2010. We've tried both & the result is the same - the emails are returned regardless of being sent through Outlook or through the webmail interface.

2. No, no recent changes to hardware, software security or network configuration.

Accepted Solution

Administrator

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1.5K Messages

7 y ago

Hello Iworxtech,

 

We have engaged our security assurance team to assist you in this query.

But for the community, can you clarify item for us?

 

1. How do send your emails?

- Email client or Webmail

 

2. Did your company make any changes to your network recently?

- Such as new filter/firewall

 

Thank you

Advocate

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1.4K Messages

7 y ago

Hello lworxtech,

 

Could you make sure that your out going port on all your email users in Outlook exchange or webmail is not set to port 25 because Comcast now blocks this port. If you find any of your users using port 25, then if you are within Comcast network use port 587 and if off network use port 465.

 

Hope this helps you out.  

New Contributor

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12 Messages

7 y ago

No one is using port 25.

There was a time on Friday when mails began to go through again, but the bouncing has resumed since - same domains.

Administrator

 • 

1.5K Messages

7 y ago

Hello Iworxtech,

 

Our security team informs me they have reached out to on Friday.

We will engaged them again to assist.

 

 

Thank you

 

New Contributor

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12 Messages

7 y ago

Thank you : )

New Contributor

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12 Messages

7 y ago

Well, all was good for a while, until today - the 550s have resumed : (
. . . though this time on a different server (not 76.96.107.73 - that one seems clean again).

Here's the latest . . . please help, thanks : )

Reporting-MTA: dns; omta02.potomac.co.businessclass.comcast.net [76.96.107.72]

Received-From-MTA: dns; CH1HUB01.CH1.COMCAST.NET [172.28.148.146]

Arrival-Date: Mon, 10 Mar 2014 20:06:23 +0000

 

Final-recipient: rfc822; xxxxxxxx@mjm.com

Action: failed

Status: 5.1.1

Diagnostic-Code: smtp;  550 Connection refused

Last-attempt-Date: Mon, 10 Mar 2014 20:06:23 +0000

 

Administrator

 • 

1.5K Messages

7 y ago

Hello Iworxtech,

 

Thank you for the posts to issue.

We have engaged our security team to assist.

 

 

Thank you for your patience.