Any idea why my custom domain does not work? dig +short MX peterge.de works... reddit / selfhosted ---------------------------------------------------------------------- peterge98 · 2023-12-12 11:03 ​ looks fine too in the webinterface ---------------------------------------------------------------------- mwdmeyer · 2023-12-12 11:12 DNS looks ok [https://auditdns.net/?domain=peterge.de](https://auditdn s.net/?domain=peterge.de) What are you using to test? ---------------------------------------------------------------------- peterge98 · 2023-12-12 11:13 I use the webinterface of my mail provider: [mailbox.org](https://mailbox.org). Thats where the error message came up which i screenshoted ---------------------------------------------------------------------- jusepal · 2023-12-12 11:15 Something is wrong with your dnssec. Double check your setting at either your registrar or your dns hosting. If you just did anything that effected dns like moving registrar or moving dns hoster, wait a few hours for the records to expire and check again. https://dnssec-analyzer.verisignlabs.com and https://dnsviz.com is where you can check dnssec status. ---------------------------------------------------------------------- peterge98 · 2023-12-12 11:16 I just have a box for eenabling and disabling dnssec... ---------------------------------------------------------------------- Alternative-Mud-4479 · 2023-12-12 11:17 That error is most likely because peterge.de does not have an A record in DNS. ---------------------------------------------------------------------- peterge98 · 2023-12-12 11:18 Its because I just use subdomains to access my services. What should the host look like for my A record? ---------------------------------------------------------------------- Alternative-Mud-4479 · 2023-12-12 11:19 Just make it point to anything, doesn’t have to actually go anywhere or do anything functional. ---------------------------------------------------------------------- peterge98 · 2023-12-12 11:20 I would just set it to the ip of my vps. But what do I need to enter in the host field? just leave it blank? ---------------------------------------------------------------------- Alternative-Mud-4479 · 2023-12-12 11:21 For root level use @ ---------------------------------------------------------------------- peterge98 · 2023-12-12 11:23 okay then this might be the reason. I deleted it because i thought @ is something related with mail... stupid me ---------------------------------------------------------------------- Alternative-Mud-4479 · 2023-12-12 11:30 Yeah, that definitely would do it. I always find it odd that some mail servers need an A record to exist when there’s already an MX record for the domain, so it’s obviously valid. ---------------------------------------------------------------------- FuriousRageSE · 2023-12-12 11:58 > If you just did anything that effected dns like moving registrar or moving dns hoster, wait a few hours for the records to expire and check again. This is why i always chose the lowest possible TTL when i add dns, a small f-up shouldnt take days to clear up, before i can use/access/do what ever i needed/wanted to. Not sure what the good/bad part of having really low TTL other than a small f-up can be fixed in minutes instead of days. ---------------------------------------------------------------------- FuriousRageSE · 2023-12-12 11:59 Im guessing its one of the way trying to combat spammers. So you need to setup a "website" to be able to send mail.. i guess.. but how hard is it to point @ to any ip when its not even verified that the ip is yours to begin with. ---------------------------------------------------------------------- hexathos · 2023-12-12 12:41 isn't there a verification txt record missing? maybe [mailbox.org](http://mailbox.org) disabled the domain for sending because of that ---------------------------------------------------------------------- Substantial-Moron · 2023-12-12 22:17 /u/peterge98 This is definitely a thing. T-Online.de will block your emails for example if you do not have website. ---------------------------------------------------------------------- grumpyGrampus · 2023-12-13 05:32 For my edification, what does an A record have to do with email? ---------------------------------------------------------------------- peterge98 · 2023-12-13 06:01 Good to know ---------------------------------------------------------------------- Alternative-Mud-4479 · 2023-12-13 11:20 As far as I understand it, it’s used only for a domain validity check to make sure the “From” domain actually exists. There are probably other ways this could be done, but this is likely the quickest. ---------------------------------------------------------------------- KD_done · 2023-12-13 22:10 So.. lets dive into this rabbit hole. An MX record looks a little like this; Lets take google as example; [google.com](https://google.com) IN MX [smtp.google.com](https://smtp.google.com) 10 300 or, as dig would show; google.com. 300 IN MX 10 [smtp.google.com](https://smtp.google.com). So.. it tells me that the record I looked up is for mail (MX), valid for 300 seconds, and has a priority of 10 (if your have multiple MX records, the lowest number is the highest priority (mathematical sorting says lower is first)). The host it refers to is [smtp.google.com](https://smtp.google.com) .. and that's the A record we are looking for as an MX record can not point to an ip address. The A record a lot of people talked about. So, if we pull apart the [smtp.google.com](https://smtp.google.com) A record, we get the following; smtp.google.com. 300 IN A 74.125.206.27 smtp.google.com. 300 IN A 66.102.1.26 smtp.google.com. 300 IN A 74.125.206.26 smtp.google.com. 300 IN A 66.102.1.27 smtp.google.com. 300 IN A [64.233.184.27](https://64.233.184.27) And now we know what servers/nodes we can talk SMTP to! Commands used are; dig -t MX [google.com](https://google.com) dig -t A [smtp.google.com](https://smtp.google.com) Regarding OP's problem; the 4xx error of the post however, show that the MTA (the recieving server) states that the domain is not configured for the mailserver.. so, the MTA refuses to accept any traffic for said domain. I doubt his problem has anything to do with DNS, but misconfig of said mailserver. ---------------------------------------------------------------------- grumpyGrampus · 2023-12-14 06:34 Thanks for this. I was not thinking about the MX record referring to a domain that must be resolved with an A record. ---------------------------------------------------------------------- KD_done · 2023-12-14 08:47 Your welcome! If a server is to be reached under a name, it must point to an ip address. There are many.. MANY different types of records, and honestly.. only SOA, MX, A, CNAME, TXT are used (I hardly ever add anyhting else on production boxes). And of those records, only the A points to an ip address. So don't be to harsh on yourself :)