cross-posted from: https://sopuli.xyz/post/12515826

I’m looking for an email service that issues email addresses with an onion variant. E.g. so users can send a message with headers like this:

From: replyIfYouCan@hi3ftg6fgasaquw6c3itzif4lc2upj5fanccoctd5p7xrgrsq7wjnoqd.onion  
To: someoneElse@clearnet_addy.com

I wonder if any servers in the onionmail.info pool of providers can do this. Many of them have VMAT, which converts onion email addresses to clearnet addresses (not what I want). The docs are vague. They say how to enable VMAT (which is enabled by default anyway), and neglect to mention how to disable VMAT. Is it even possible to disable VMAT? Or is there a server which does not implement VMAT, which would send msgs to clearnet users that have onion FROM addresses?

  • mark@infosec.pub
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    7 months ago

    That is 100% what im saying, yes. The sending server needs to sign all messages with a private DKIM key where the public key is in a dns text entry. Then the reverse dns lookup for the mailserver needs to match the SPF txt record. Then your DMARC record has to match the dkim and spf settings.

    Ive set this up for exchange at work as well as my own personal mailserver, which is just a debian server running postfix and dovecot.

    When you want to use gmail as a mailserver for your own domain, you set these three things up so that your messages arent all blocked.

    Keep in mind, you do not need these to simply send and recieve messages, but if you want to interact with the rest of the world you do. Email is too easy to spoof, so everyone has agreed on these protocols for authenticity.

    • freedomPusherOP
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      7 months ago

      That is 100% what im saying, yes.

      Okay, so AFAICT you’ve not said anything that prevents individual users from using an onion FROM address, so long as the sending server is authorized via all the shitty spf, dkim, dmarc, dane hoops. This is what I’m after. In fact, I’m even less demanding. I don’t care if a service provider doesn’t bother with dkim and gets rejected by some servers. Email is in such a broken state anyway… I just need the option to set the FROM field to an onion address. The reason my own server is insufficient is the residential IP is very widely rejected.

      • mark@infosec.pub
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        7 months ago

        No you can totally modify mail headers anytime you want to, just be prepared to get mail rejection if you’re not following current mail security best practices.

        I’d recommend just renting a cheap vps from vultr or something, then you can setup your mailserver to send from anything you like. That’s how my mailserver works. I pay like $3 a month, and its plenty of space for a single user mailserver (i have like 3 mailboxes)

        I did go through the work to setup dkim/dmarc/spf. Took a weekend, but wasnt too bad. My mail is received by gmail yahoo and Microsoft. I imagine doing the same with onion addressing would be complicated.