Exim headers_rewrite - Relay
Hello good afternoon.
We are currently integrating our cPanel servers with an external relay.
This relay will perform the cleaning of emails, in addition to speeding up delivery.
One of the points of this external relay is that it allows transmitting e-mails only from correctly configured domains, that is, SPF and DKIM, so the e-mails that are retransmitted are not taxed as spam.
So far no problem, everything working very well.
The problem happens when I create a forwarder in cpanel, as follows:
xxxxxxxxx@gmail.com - Original Sender
xxx@mydomain.com - Original Recipient
xxxxx@hotmail.com - Forward Recipient
(These are just examples, original sender and forward container can be from any domain)
We currently use customizations in the following items from exim to allow the relay of emails from the server.
Section: AUTH
Section: ROUTERSTART
Section: POSTMAILCOUNT
Section: TRANSPORTSTART
I would like your help to know what exactly I have to do to allow emails to be forwarded through the original recipient.
Remembering that we have already activated SRS on cpanel without success for this specific case.
In contact with cpanel support, we were informed that we would have to adjust
headers_rewrite
But due to our low familiarity with exim, we are not able to make such adjustments.
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Can you provide the ticket ID here for your cPanel support ticket so I can get up to speed as to what was already investigated? 0 -
Hello thanks for your reply. Our ticket number is #93475276 Can you provide the ticket ID here for your cPanel support ticket so I can get up to speed as to what was already investigated?
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Thanks for that. Their explanation was a lot more detailed than just change headers_rewrite and they provided resources for you: [QUOTE] This is not working because our SRS feature is not designed for the task that you are attempting to use it for. The SRS feature only does very minimal rewriting for the purpose of allowing PTR checks to pass. Here is an example of how it works: user@gmail.com - Original Sender gk2@domain.com.br - Original Recipient anderson@domain2.com.br - Forward Recipient The message is received by cPanel from user@gmail.com. During the forward, cPanel rewrites the email address from user@gmail.com to something like the following: srs0=vzcsgv=wz=gmail.com=user@domain.com.br Notice that the SRS feature intentionally retains all of the original information in the from address to ensure that it is possible to track down abuse, but it does so in a way that allows for the PTR check to pass. It is my understanding that in order for your remote relay server to accept the message, you would need for Exim to rewrite the sender information entirely so that messages from user@gmail.com would be rewritten to appear to come from gk2@domain.com.br .
This isn't something that the SRS feature does and it isn't a functionality that is performed by cPanel. They also suggested you use the headers_rewrite option as noted in the exim documentation: [QUOTE] The Exim documentation goes into depth about how to setup this kind of configuration here:0 -
Hello. I apologize if at any time I have implied that the support was not efficient or did not answer me, it really was not what I meant. My intention in coming here on the forum was precisely to try to find a solution to this issue, once I understood that I will have to change some settings in exim. I understand that here there must be people with great exim knowledge and this may not be something out of this world, since we are not inventing something new. What we are looking for is to relay emails through a relay. Our intention is to unify dozens of cPanel servers by sending emails through a single location with hundreds of ips. This makes delivery more efficient, and of course the entire administration. 0 -
Not at all I just wanted to make it clear that there was a lot more to that response which was really informative and knowing the whole story/as much information as possible is always helpful to find resolutions to issues like this. Now, I don't see that you've noted what service you're using to relay in the ticket, or is this a relay that you've set up on your own? In a lot of cases providers that do this will have options for forwarded mails, otherwise, the technician is correct and if you're unfamiliar with exim and uncomfortable with making the modifications in the exim documentation you would need to contact a system administrator.
This was also a really important question because it could help save you a lot of time (potentially)0 -
This is a relay that I set up on my own. We only accept domains that have been previously configured (SPF and DKIM), so emails are sent without further problems. The problem is when message forwarding happens, we are unable to relay, since this message comes from gmail.com and not from the domain hosted with cpanel. 0 -
Ok, so there won't be any easy solutions for this as is sometimes the case with services who develop their own relays. Your only option would be to use the exim documentation to come up with a solution our SRS which does perform a rewrite does not do an exact match but that is a requirement of your relay. With the configuration you have, I don't see another way around this than using headers_rewrite. Some further resources on how to accomplish this: This is an example of a system filter a user added: 0 -
Hello good day. I will look for someone with exim experience to assist us in this project. While I can't find this professional, I've been thinking about a temporary way to solve the problem. One of the ways to do this is by identifying messages that are forwarded, so we would make adjustments to the relay. For that reason I ask if I can add something like: forwarder: yes If I can add this in the header, I can identify this message as forwarded, after that I can try to make adjustments to the email header in the relay How could I add this information to cpanel? Considering all emails that are automatically forwarded. 0
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