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Comcast Email Issues

Port 25 SMTP blocked

Port 25 SMTP blocked – Thanks for the heads-up Comcast!

Well to start the new year off right, it would seem that Comcast/XFinity is rolling out some less-than well known or publicized updates for their Internet customers.  While the reasons for this change are many (and understandable with some background information), the fact that it is not more directly addressed or openly communicated with especially the business customers leaves most of us scratching our heads over the weekend.

Understandably, many ISPs (Internet Service Providers) such as Comcast have been blocking Port 25 for some time now – this isn’t new news.  However, it would seem that Port 26 – a workaround for Port 25 that has worked for years – is no longer being supported and/or is now being blocked as well.

For years, it has been well known that spammers use Port 25 to send out hundreds or even thousands of unwanted emails every day.  They have even gone as far as creating malware, viruses, worms and so forth to forcefully take over your computer and your email to do their dirty deeds for them – mostly without the knowledge of many people!

To combat this, many ISPs have been blocking the use of Port 25 which allows for an unsecured connection to the ISP’s SMTP (i.e. out-going) email server.  It would appear that Comcast is no longer supporting the use of Port 26 as a workaround for sending email through your domain-based email server using a third-party application such as Outlook or Thunderbird.  We cannot confirm this as of yet, however the Comcast/XFinity website does clearly recommend the use of Port 587.

Port 587 forces the use of a SSL/TSL (i.e. secure) connection in order to send any email.  That means if you are a Comcast customer, you must change your settings to use Port 587 and use your XFinity username and password in order to send email using Outlook, etc.

Unfortunately, not all web hosting providers support the use of Port 587 for POP3 email accounts, so you have basically these choices:

  1. Use webmail instead (if its supported)
  2. Switch to IMAP (if its supported)
  3. Switch to Gmail
  4. Fire Comcast and/or your current web hosting provider
  5. Resort to snail-mail

Fortunately however for RVHWD business web hosting customers, POP3 and IMAP are both supported as well as using Port 587 with authentication via your ISP.

2 Comments so far:

  1. […] But as luck would have it, several of our customers in the some of the southern tier states (mainly Alabama, Georgia and South Carolina) experienced a sudden issue with being able to send email out, but were receiving them just fine.  Our customers come first, so we spent several hours researching and troubleshooting the problem – the results were covered in the recent article Comcast Email Issues. […]

  2. […] Please Note: Some Internet Service Providers (ISPs) do not allow e-mail to be sent using Port 25 or 26.  If you are able to receive e-mail, but unable to send on either Port 25 or 26, you will have to use your ISP’s SMTP server to solve the problem.  For example, check out this article on Comcast email issues. […]

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