all my emails from ctrl-c.club are being rejected by the mail server and it says, `Client host rejected: cannot find your reverse hostname`. Is that something important that a mail server should implement?
Hello,
First I want to say I love your bird profile picture!
Secondly, regarding reverse hostname rejections... It is a very common practice now days, especially among the big ESPs, to not accept email when the reverse DNS does not match. The reason for this is that when it matches it significantly increases confidence that the person behind the address can be held accountable for their actions, because the person sending from that IP address has enough control over their infrastructure to make the forward and reverse DNS match. Forward records are easy to generate using systems like DynDNS (which can be abused for fast-flux spam), but reverse DNS records are harder to change. Essentially it provides a form of authentication that there is a valid relationship between the owner of a domain name and the owner of the network that has been given an IP address. While not foolproof, it can be very effective against spammers and phishers who cannot usually bypass this verification when they use zombie/infected computers to forge domains. As a result, blocking on misconfigured rDNS stops a significant amount of spam, because it blocks dial-up users, and dynamically assigned address. Many, many many mail servers refuse email with missing or generic rDNS names.
I think that you will find that the emails from ctrl-c.club will be rejected by a significant number of mail providers out there until there is a valid reverse DNS.
First I want to say I love your bird profile picture!
Secondly, regarding reverse hostname rejections... It is a very common practice now days, especially among the big ESPs, to not accept email when the reverse DNS does not match. The reason for this is that when it matches it significantly increases confidence that the person behind the address can be held accountable for their actions, because the person sending from that IP address has enough control over their infrastructure to make the forward and reverse DNS match. Forward records are easy to generate using systems like DynDNS (which can be abused for fast-flux spam), but reverse DNS records are harder to change. Essentially it provides a form of authentication that there is a valid relationship between the owner of a domain name and the owner of the network that has been given an IP address. While not foolproof, it can be very effective against spammers and phishers who cannot usually bypass this verification when they use zombie/infected computers to forge domains. As a result, blocking on misconfigured rDNS stops a significant amount of spam, because it blocks dial-up users, and dynamically assigned address. Many, many many mail servers refuse email with missing or generic rDNS names.
I think that you will find that the emails from ctrl-c.club will be rejected by a significant number of mail providers out there until there is a valid reverse DNS.
Cyanventer,
This ticket is being closed for inactivity. Please respond and reopen the ticket if you still desire assistance with this topic.
In Solidarity,
-vireo
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This ticket is being closed for inactivity. Please respond and reopen the ticket if you still desire assistance with this topic.
In Solidarity,
-vireo
PS: We need your help to continue our work – please consider donating to riseup – https://riseup.net/donate