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Comcast IP address is Blacklisted

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Frequent Visitor

Comcast IP address is Blacklisted

I'm the IT guy for my office.  My coworker is working from home and can't send any work emails or reply to received work emails.

 

This is the message he receives after attempting to send email:

"The server response is: Access denied for 67.160.211.38"

Link to Cisco Talos to confirm blacklisting. 

 

The IP address belongs to Comast and has been blacklisted which is preventing work email to pass through Comcasts servers.

 

My coworker reported this to Comcast last Tuesday and a case was created and escalated. There has been no response since then.

 

I've been through this situation in the past with other providers and was able to resolve it almost immeidately.  How is this handled at Comcast?  Why can't my coworker get any clear responses from Comcast?  It's a big interruption and incovenience during a time when we rely on our services to work properly during this shelter in place situation.

 

I can't find anything new on this topic in these forums. The ones I've found are all archived.

 

Any help appreciated.Screen Shot 2020-03-17 at 1.56.23 PM 2.jpg

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Expert

Re: Comcast IP address is Blacklisted

Was dispute ticket submitted to Cisco. When an IP is blacklisted like that, Comcast doesn’t directly deal with the entity that black listed it to remove. That’s a Cisco problem that has to be worked out through Cisco

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Frequent Visitor

Re: Comcast IP address is Blacklisted


@jweaver0312 wrote:
Was dispute ticket submitted to Cisco. When an IP is blacklisted like that, Comcast doesn’t directly deal with the entity that black listed it to remove. That’s a Cisco problem that has to be worked out through Cisco

A little more help please.  The IP address is blacklisted by pbl.spamhaus.org.  I've gone to their site to confirm blacklist and the removal process.  This is what it says:

 

Removal Procedure
Removal of IP addresses within this range from the PBL is not allowed by the netblock owner's policy.

 

Can you tell me what this means?

 

Thanks!

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Frequent Visitor

Re: Comcast IP address is Blacklisted

Same EXACT message from Outlook here. I have nothing to do with Cisco. Next answer please. Smiley Wink

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Official Employee

Re: Comcast IP address is Blacklisted

About the PBL:

 

"The Spamhaus Policy Block List ("PBL") is an international anti-spam system maintained by The Spamhaus Project in conjunction with Internet Service Providers and is used by Internet networks to enforce inbound email policies. The PBL database lists end-user IP address ranges which should not be delivering unauthenticated email to any mail server except those provided for specifically for that customer's use. The PBL lists only IP addresses (not domains or email addresses)."

The issue is likely a configuration of their email client - if they are using their Comcast email to send email they need to authenticate through the comcast SMTP server. Such is true for also domains. The outlook client should not be the "server" in this example. The user should be authenticating to its corresponding SMTP server. If Cisco is preventing authentication to your SMTP server, then you will want to have Cisco unlist so that your user can authenticate to your domain. 


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Re: Comcast IP address is Blacklisted

Thanks, for your helpful answers.  I really appreciate it.

 

We do not use Outlook. We use Apple Mail on our Macs.  The SMTP settings are all correct; domain is correct, everything.  I have Comcast also at my home, using the same settings, same setup, but no problems sending mail.  BTW, he can send email using his iCloud account with no problem.  

 

All our staff working from home are all on Macs using Apple Mail.  I have set up everyone's email settings correctly on all.  Only one coworker is having this issue.

 

So Cisco is where to go from here?