Error: Customer reported they could not send emails from their charter.net email address through mobile.charter.net over 587 SSL when they were on their Clearwave wireless network. If they turned off wifi, emails would send.
Answer: We configured Mozilla Thunderbird on their Clearwave network to use Charter, it immediately threw this error when we tried to send:
An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: impout004.msg.chrl.nc.charter.net cmsmtp *.*.*.* blocked. Please see https://www.spectrum.net/support/internet/understanding-email-error-codes for more information. AUP#Out-1130.
1100 - 1150
The IP address you’re trying to connect from has an issue with the Domain Name System. Spectrum requires a full circle DNS for emails to be allowed through. Verify the IP you’re connecting from, and check the IP address to ensure a reverse DNS entry exists for the IP. If the IP address is a Spectrum-provided email address, contact us.
Summary: It seems, as a security measure, Spectrum will not let your IP connect to their outbound email relay servers if your public IP does not have a PTR / reverse lookup DNS record, of any kind. It just needs to exist, it does not have to match your company name or domain name or anything.
We contacted Clearwave support and requested a DHCP PTR record be created. They obliged and created it. Mozilla was able to send emails and their phone worked too. NOTE, with a dynamic address, if their IP changes, they will have to contact support again, but it works for now.
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