about half a year ago we started having problems with forwarding emails to some servers including Gmail etc. It seems that Google and others have started to enforce a strict SPF policy and forwarded emails from domains with strict SPF settings are no longer accepted.
A solution to this problem seems to be the so-called SRS or Sender Rewriting Scheme, which rewrites the sender’s address. The procedure and patch for qmail is available here. However it seems it is not included in qmail distributed with Interworx.
It is very surprising that no one has asked about this problem here on the forum yet. Are we the only ones who have encountered it? Does Interworx include some other solution for it?
I can honestly say this has never come up, before. Can you provide more information as to google blocking forwarded messages? No one has ever reported that as an issue, though it is well known that Google expects domains to have SPF, DKIM, and PTR records. It would be odd for google to block messages from domains that have SPF records.
Thanks,
-Jenna
Friendly Neighborhood InterWorx Support Manager
SRS allows a mail server to rewrite the From address to allow the middleman mail server to forward on a received email without triggering SPF restrictions from the forwarded recipient mail server.
This solves the problem that mail forwarding (alias) accounts have. For example, mail sent by Google to somealiasaddress@interworxhosteddomain.bfr which is a mail forwarder that then relays the mail to the final destination address finaluser865432@outlook.-com. Outlook.-com would look at the header and refuse the mail because the “interworxhosteddomain.bfr” mail server is not allowed to send mail for google. SRS adjusts the header so that outlook.-com won’t refuse it because the header makes it clear the message is being forwarded from “Interworxhosteddomain.bfr”.
A lot of mail servers have adopted this because otherwise forwarding received mail won’t work for mail servers that check SPF on receipt. It’s been a thing, for example, on Plesk (Linux) and cPanel servers for a long time.
It would be very useful to have the option to enable this.
I talked to the dev team and submitted a feature request, though I do not have an ETA at this time.
Note–both cPanel and Plesk use Exim for their mail service, not qmail, so there is a bit of a difference as to how something like this would be handled, just in general.
I know the stacks are different, but Muad already linked to the qmail patch and, like it or not, cPanel and Plesk are exactly the products Interworx gets compared to. Most end users don’t care about the stack (the how), only the feature set (the what). It may not be fair, but such is the world.
Anyway, thanks for considering the feature. Getting forwarding working again would be useful.
For the record, there are many reasons Gmail blocks forwarded email, and given that every email client can be configured to log in to multiple accounts, you should encourage your customers to log into your system for their email rather than forwarding. As well, forwarded ‘spam’ can ruin your whole systems reputation with Gmail. A few expert tips? Turn off IPv6 for email, only use IPv4, Gmail is more lenient with IPv4. Ensure DKIM for domains forwarding to Gmail. Watch SPF for those domains, forwarding may break SPF.
There is an open feature request, but it has not been accepted, yet. I will bump it, though.
There are eventual plans to move to Exim, however, that is a very, very large change, since it would be a complete overhaul of our mail system, and I do not have an ETA at this time, as there are other, higher priority large projects in active development (we are also a small team. There are only five devs and myself, and we are also beholden to a parent company who has a large stake in what we focus on at any given time).
i have had this discussion with many clients about forwarding emails to their Gmail.
there biggest/most common reason they do this is to save cost of google workspace to handle their mail the other reasons given where they are just where not aware of google workspace as a service and how easy it is to setup even with there siteworx hosting.
We have banned permanent forwarding and employed an smtp service smtp2go have been great at deliverability.