From 519994cfdf82869610fbd09fa5bc1cbe8cd1f848 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Sapka?= Date: Sun, 15 Jan 2023 17:46:43 +0100 Subject: feat: dns error article --- .../2023/wildcard-mx-and-a-dns-record-conflict.md | 23 ++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 content/2023/wildcard-mx-and-a-dns-record-conflict.md (limited to 'content/2023') diff --git a/content/2023/wildcard-mx-and-a-dns-record-conflict.md b/content/2023/wildcard-mx-and-a-dns-record-conflict.md new file mode 100644 index 00000000..bff9f1df --- /dev/null +++ b/content/2023/wildcard-mx-and-a-dns-record-conflict.md @@ -0,0 +1,23 @@ +--- +title: "Wildcard Mx and a Dns Record Conflict" +category: "blog" +date: 2023-01-15T17:43:42+01:00 +draft: false +tags: ['dns', 'mx-record', 'a-record', 'email'] +--- + +A random problem I've just encountered by discovering that my email is broken. You can have a wildcard MX record (*.domain), which will handle all subdomains not defined by other records. + +>>> A common + mistake is thinking that a wildcard MX for a zone will apply to all + hosts in the zone. A wildcard MX will apply only to names in the + zone which aren't listed in the DNS at all. +>>> [RFC1912](https://www.rfc-editor.org/rfc/rfc1912) + +So, in this case, an A record for test.domain will break the email for test@domain. Solution: add a dedicated MX record for this domain (MX test.domain) with the same value as the wildcard. Now, even if the wildcard one is ignored, the client will fall back to the new record. + +``` +*.domain MX 10 addr +test.domain A 10 adddr2 +test.domain MX 10 addr +``` \ No newline at end of file -- cgit v1.2.3