Forum Discussion

VeryCoxWeary's avatar
New Contributor

Is Cox limiting IMAP or SMTP functionality for those Cox customers who use a VPN or different domain?

I always use a VPN when banking or logging on to my billing accounts, etc.  Given the hacking going on, a VPN is really essential.

I use Thunderbird as my email client and have for years.  I receive and send GMAIL, my private email which comes from my private domain that I have hosted by a large hosting company for years.  Until today, I have never had any problems sending or  "" mail through Cox's SMTP server.  When I tried it today, with my VPN on, here is what I got:

"The mail server sent an incorrect greeting: cox connection refused from"

The IP address belongs to my VPN company's Phoenix server.  

On first blush, I wonder if this could be due to one of two (or more) things:

1) Is Cox all of a sudden only allowing emails to be sent through it's SMTP server from a Cox leased IP address. (in other words, not via my VPN)...  or...

2)Is Cox prohibiting the sending of anything other than an email with a Cox domain through it servers.  I hope this is not so,  I pay over $100/month for Internet service and want to continue using Cox's SMTP server to send all of my mail, as I don't want to have to select from multiple SMTP servers in Thunderbird's settings each time I use a different email alias.  Yahoo is doing this and it is a real problem...they do this to force you to use their Yahoo Mail app and NOT a client.   I don't like ad-filled Yahoo Webmail and I am not enamored with Cox's "NEW" Webmail either.  A separate email client allows rapid mass deletion of garbage mail without clicking boxes , etc.

Thanks in advance for your response.

4 Replies

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  • ChrisL's avatar
    Former Moderator

    If your Internet connection is not recognized you may need to verify your identity in order to continue accessing certain services so as to minimize the risk of your account being compromised. I'd suggest trying to sign into your account while you're on the VPN. If you're prompted for the 2 factor authentication your IP should be whitelisted for 60 days which would allow the SMTP to function again.

  • This blocade just started recently???  Did Cox just throw the switch on this?  I got one more message today.  I have not been able to send email from Thunderbird for DAYS!

    " The mail server sent an incorrect greeting: cox connection refused from"


    THIS IS A BRIDGE TOO FAR!!!!!!!!!!!!!!!

  • Jerry's avatar
    Contributor II

    With, "...all the hacking going on...", and a VPN being, "...really essential.", doing a two factor sign-in once every 60 days for an extra level of security is a bridge too far? Hmmm.

    Why do I have to put my key in the deadbolt as well as the doorknob every time I come home?

    Why does my bank ask for my ID and then force me to enter my PIN in that little pad just so I can cash a check?

    Why does my computer ask me if I really want to delete a file right after I just told it to delete the file?

    Why do I have to step on the brake pedal before my car will let me shift into reverse?

    Etc., etc., etc.

  • Jerry,

    I guess I must be dense because I don't understand your "subtle" comments.

    Cox should NOT be blocking the sending or receiving of email based upon the domain in that email address.  There are other heuristic and algorithmic methods available to Cox that would prevent spamming and still provide bonafide customers with the liberty of using enhanced encryption via an encrypted VPN tunnel.  Cox started this "killing a fly with a sledgehammer" behavior in the 1990s by blocking Port 25. 

    Email clients like Thunderbird (Mozilla) or Evolution and Kmail (Linux) do not perform dynamic SMTP server addressing.  Yahoo started making the sending of email for generic email clients impossible, and it looks like Cox is now behaving similarly....making it impossible to send email with your domain with a connected VPN.  If Cox and other providers, as well as banks and other financial institutions have a right to use encryption in its many forms, they should not be blocking "the little people" like us from employing similar data protection efforts to protect our private transactions.