LuKreme wrote: > No, you're still not understanding. > > Say you have a ... oh, I dunno, a DHCP server/router that your entire > office network plugs into. And say it has a feature, as so many do, to > send alerts via email if say the uplink goes down. Now, that email > configuration is very primitive, has almost not options, and also > doesn’t likely have rDNS configured correctly on it. > > When the uplink goes down and the emails get rejected, there's no one to > know. The human is involved, you just don't get the alert you are > expecting when you expect it. > > Who gets blamed when it's discovered all those emails where never > delivered? The person in charge of the mailserver.
a) on your internal network you may violate as many RFCs as you want (if doing so makes you feel better) b) do not expect to see mail from a missconfigured server in your G/Hot/ Whatever-Mailbox c) how do you send mails if your uplink is down? d) the person who did not correctly set up the network is to be blamed, if you have equipment acting as MTA it should be configured the right way, otherwise use a relay server e) we are a really small ISP, but the largest one in our region. Two years ago we decided to be less permissive - and we had to dedicate ressources to teach people what they are doing wrong. The result has been, that other providers in our region are now doing the very same thing, and if someone complains they take us as a reference "They are also doing so, many ISPs do so - fix your system, don't blame us". It's all just a matter of time - and as more and more very large Mail providers are enforcing correct behaviour it is becoming much easier to set up such restrictions. The times where everyone could blindly send out mail from missconfigured hosts are over. Climate has become rough, you're left with the option to either take care of your MTAs, to use a correctly configured relay or to live with the fact that your mails will not be able to reach more and more people. As we have read before, rejecting mail from human senders is fine, as they will receive the bounce - and hopefully take care to find someone able to fix the problem. Much worse are automated mails from missconfigured systems, with no one taking care of bounces / rejects. You'll met public entities, booking confirmations from cheap airlines running lots of mailservers etc. That's nasty, your users will complain - and you should be prepared to (temporarily) add some IP to your whitelist and to immediately give them a competent answer: the opposite site is behaving wrong, you are just enforcing MTAs to respect a small subset of current standards. Regards, Thomas Gelf
