Sender Policy Framework added for dotnetphen.com

Today I designed the SPF-record for my domain and sent it to my provider. Hopefully it is added to the dns the next days.

SPF stands for "sender policy framework" and is, simply said, a dns text-entry that specifies all mail server that are sending mail from a domain. For my domain this is for example "v=spf1 a mx ~all". This SPF record can be explained as:

• v=spf1
  This identifies the TXT record as an SPF string.
  
• a
  dotnetphen.com's IP address is 88.80.208.233 (vcvps1043.vcdns.de). That server is allowed to send mail from dotnetphen.com.
  
• mx
  This wizard found 2 names for the MX servers for dotnetphen.com: mail and vcvps1043.vcdns.de (A single machine may go by more than one hostname. All of them are shown.). The servers behind those names are allowed to send mail from dotnetphen.com.
  
• ~all
  SPF queries that do not match any other mechanism will return "softfail". Messages that are not sent from an approved server should still be accepted but may be subjected to greater scrutiny.
  

My mail server sends data with the hostname mail.dotnetphen.com, but my provider added two mx records to the dns. So we have to get rid of the one record that isn't used; we create a second spf entry that points to the active host. After that it has to look like this (in bind syntax):
dotnetphen.com. IN TXT "v=spf1 a mx ~all"
mail.dotnetphen.com. IN TXT "v=spf1 a -all"

The first entry specifies my mx-servers to be "ok", the second on specifies the host with the name mail.dotnetphen.com to be the mx record used to send mail.

To support admins during the sender policy framework setup process the SPF Project Site has a SPF Setup Wizard that is a great help to get a fast start.