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Does one's ISP affect mail delivery/blacklisting?

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es33
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Does one's ISP affect mail delivery/blacklisting?

This might be a silly question, but does one’s ISP affect mail delivery/blacklisting, or just the mail server?

 

We use Office 365 (Exchange Online) for mail, which is not on any blacklist.  However, we use Comcast Business for internet, and our dynamic ip is currently showing up on a few blacklists.

 

Will this affect our mail delivery – and if so, are we better off switching to a static ip?  We never considered static before since we don’t host our website, but if it helps with mail delivery we'll do it.

 

Can you please advise?

 

Many thanks

Accepted Solution

Re: Does one's ISP affect mail delivery/blacklisting?

No, you should be fine. The blacklisting you mention (done by SORBS, and reported in numerous places by things such as the ICSI/Berkely "Netalyzr") is meant for people hosting mail servers. As a spam precaution, ISPs publish lists of their dynamic IP address ranges, and make the assumption that no one legitimate will be running a mail server on those IPs, implying that if mail is being hosted there, it is likely a spam or bot-infected computer. But when you send mail via Exhange Online, your mail is hosted/served on Microsoft's mail servers; you just connect via HTTP or POP3/IMAP from your Comcast connection, and it's NOT necessary to have a static IP to do that (indeed, if it were, no one on residntial service would be able to send/receive mail, as they are all dynamic IPs with no static option available.)

 

Unless you intend to run a mail server at your physical location from your physical Comcast connection, you should be totally fine with a dynamic IP.

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Trusted Forum Contributor

Re: Does one's ISP affect mail delivery/blacklisting?

No, you should be fine. The blacklisting you mention (done by SORBS, and reported in numerous places by things such as the ICSI/Berkely "Netalyzr") is meant for people hosting mail servers. As a spam precaution, ISPs publish lists of their dynamic IP address ranges, and make the assumption that no one legitimate will be running a mail server on those IPs, implying that if mail is being hosted there, it is likely a spam or bot-infected computer. But when you send mail via Exhange Online, your mail is hosted/served on Microsoft's mail servers; you just connect via HTTP or POP3/IMAP from your Comcast connection, and it's NOT necessary to have a static IP to do that (indeed, if it were, no one on residntial service would be able to send/receive mail, as they are all dynamic IPs with no static option available.)

 

Unless you intend to run a mail server at your physical location from your physical Comcast connection, you should be totally fine with a dynamic IP.

es33
New Member

Re: Does one's ISP affect mail delivery/blacklisting?

Thanks train_wreck.

 

We've been getting a lot of bouncebacks lately saying our email was flagged for spam, so just trying to narrow it down.  Sounds like I can scratch our dynamic IPs off the list.

Tnelsom
Contributor

Re: Does one's ISP affect mail delivery/blacklisting?

It sounds like what you are getting is back scatter... What you may be seeing is somewhere in the world a spammer is using your email address as the from address in their spam. We had a client that started getting Russian bounce backs because of this.
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