I have one feature I really need. When verifying, in this case recipient verify, I need to be able to read the string I get back from the target server.
I'm in the front end spam filtering business. Most of what I do is front end filtering. The set their MX records to me, I fliter the spam, and forward the good email to the original server. When people sign up I read their current lowest MX and add it to a table that is used to forward the mail to when I get done with it. Generally it works well. When I get an incoming email I do a forward callout to the recipient server to verify that the recipient is good. If the target server rejects the recipient in the RCPT TO phase then I reject the incoming email indicating that the user doesn't exist. Here's the problem I'm trying to solve. The user changes their MX records to my servers and at first everything works. Then 2 hours later I get a call saying that email is being bounced. What happens is that in some cases the original server thinks it is no longer the server for that domain because it is no longer the lowest MX record so it replies that my server is not authorized to relay through their server. What I need to do is detect that this is happening and at least store the incoming email and alert me that there's a problem. I have yet to find a solution. But if I could do a callout and look at the response to see if the word RELAY is in it then that would be a very good indication that the target server is misconfigured. Similarly, and this happens less often, that because all the email for the domain is coming from a few IP addresses that I run into rate limiting. Too many connections from one IP address. This results in delayed email and I am usually not aware of the problem until the customer complains. I would also like to get the response from the target server on 550 errors so that I can put it in my log files so I can review why the target server rejected email. Some times the target server is also still running spam filtering and it rejects on a false positive on their end. That would be something I'd like to be able to log so that I can find the problem. Thoughts? -- ## List details at http://www.exim.org/mailman/listinfo/exim-users ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://www.exim.org/eximwiki/
