Posts tagged e-mail
Setting up a backup MX host with Postfix
- 21 July 2023
Running a backup MX host is a good idea if you want to ensure that e-mails are not lost if your primary MX host is down. With Postfix, this is easy to set up on a Debian or Ubuntu system as both are shipped with Postfix.
Mail servers that are misconfigured can be used to send spam. Therefore, you should closely monitor your mail server and make sure that it is not misused by spammers. In case of any doubt, you should shut down your mail server immediately.
Removing SPF Resource Records
- 13 December 2017
With the creation of RFC 4408 also new a record type 99 for DNS was created to identify SPF Resource Records. It was advised to have both TXT and SPF records in DNS with the same content. RFC 4408 was obsoleted by RFC 7208 in 2014 with paragraph 3.1 stating the following:
SPF records MUST be published as a DNS TXT (type 16) Resource Record (RR) [RFC1035] only. The character content of the record is encoded as [US-ASCII]. Use of alternative DNS RR types was supported in SPF’s experimental phase but has been discontinued.