Minimizing SPF servers.mcsv.net

Suggested SPF records: (One query compared with one query originally)

HostnameValue
servers.mcsv.net (117 bytes)
 "v=spf1 ip4:205.201.128.0/20 ip4:198.2.128.0/18 ip4:148.105.8.0/21 ?all"
Suggested SPF records in bind zone file format:
servers.mcsv.net.	3600	IN	TXT	"v=spf1 ip4:205.201.128.0/20 ip4:198.2.128.0/18 ip4:148.105.8.0/21 ?all"

The DNS queries used to retrieve the original set of SPF records:

QueryResponse
servers.mcsv.net TXT
 servers.mcsv.net TXTv=spf1 ip4:205.201.128.0/20 ip4:198.2.128.0/18 ip4:148.105.8.0/21 ?all

About SPF Minimization

This tool reads an existing set of SPF TXT records, then rewrites a subset of them into a new set of TXT records. The new set of records will express exactly the same SPF data as the original set of records.

After being minimized the SPF data will often be expressed in fewer TXT records; this helps you and your customers avoid problems with too many DNS queries leading to invalid SPF.

You shouldn't use this tool blindly to squash your existing SPF records into new ones. In particular you should only select for inlining included SPF records that are under your control. You should leave any included SPF records that are controlled by other people as not inlined (if you don't, then your records won't be updated when the included records are).

If you are minimizing an SPF record that you expect your customers to include, e.g. spf.example.com, then you should start by entering "spf.example.com" into the SPF minimizer, press the Minimize button, then check the "inline" checkboxes for only those included SPF records that list your mailservers. Finally click "Update Inlines" to create a suggested new set of SPF records.

If you are minimizing the SPF record for your own domain, e.g. example.com, then you should start by entering "example.com" into the SPF minimizer, press the Minimize button, then check the "inline" checkboxes for only those included SPF records that list your mailservers, not those that your email providers asked you to include. Finally click "Update Inlines" to create a suggested new set of SPF records.

What else can you do to minimize your SPF records? Avoid using the "mx" entry in your SPF records - it's rarely needed at all, and you can replace it with ip4 and ip6 entries for that server. Also, look at the address ranges you list - if multiple ranges can be replaced with a single larger range that can save some space.

Notice: This is a new tool - you should check that it's suggestions look reasonable before relying on them in production.