Bypass RBL for authenticated user

[twoup]

Hi,

I cannot find an actual solution for this anywhere.

I have some uesrs who use ISP's who list their customer DHCP IP's in spamhaus, etc. All users are required to authenticate to send messages through the server, however users on these IP ranges have their submissions rejected based on RBL lookup. An example from the log file:

Code: Select all

2019-08-20 15:39:19 H=<CUSTOMER HOSTNAME> ([192.168.0.26]) [<PUBLIC IP>] X=TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256 CV=no F=<[email protected]> rejected RCPT <[email protected]>: Rejected because <PUBLIC IP> is in a black list at zen.spamhaus.org

I've tried adding the public IP to the "white-blocks.conf" file with no success. This would be difficult to manage anyway, as the offending addresses change daily.

Any suggestions on how to permit authenticated users to send from RBL blocked addresses?

Thanks,
Twoup.

[twoup]

Never mind - this is already the case it seems. I have managed to test a device on the same dynamic IP range as the problematic user, and it looks like they have a client side configuration issue (not sending AUTH for SMTP).

[sysdop]

As the error message says your server's IP is expelled in Spamhaus for problems with spam, you must use a service such as Sendgrid to relay SMTP and fix this issue.

[twoup]

As the error message says your server's IP is expelled in Spamhaus for problems with spam, you must use a service such as Sendgrid to relay SMTP and fix this issue.

The *client* IP is is SpamHaus. My Server IP is fine. Also, the solution suggested is incorrect. If your IP is in SpamHaus, you should work with your ISP (if they'e added it as part of a dynamic range). If your IP isn't listed in SpamHaus by your ISP, you should work with SpamHaus to discover why you were listed and get yourself delisted.

Using third party providers, such as Sendgrid (as mentioned) and ReturnPath, should be a last resort, as that causes certain large "freemail" proveders to start closing the doors to legitimate third party providers, which is ironic as freemail providers are some of the worst sources of Spam out there.