Create both IPv4 and IPv6 SPF record

Question

Right now I have SPF IP4 and IP6 as two separate records, but IPv6 is not being recognized by Gmail. Should I merge them? It looks like this currently. How should it be configured?

  A   3600     0  78.46.138.249
 MX   3600    10  mx.zohomail.com
 MX   3600    20  mx2.zohomail.com
 NS   3600     0  ns1.loopia.se
 NS   3600     0  ns2.loopia.se
TXT   3600     0  "v=spf1 ip4:78.46.138.249 ~all"
TXT    300     0  "v=spf1 ip6:2a01:4f8:d16:1355::2 +all"

GMail:

Received-SPF: softfail (google.com: domain of transitioning [email protected] does not designate 2a01:4f8:d16:1355::2 as permitted sender) client-ip=2a01:4f8:d16:1355::2;

Solution 1

I think this is a duplicate of Will adding a second SPF record mess up my DNS? on Server Fault.

In short: yes, you must merge them. The specs do not allow multiple SPF records.

The resultant merged record should be:

TXT "v=spf1 ip4:78.46.138.249 ip6:2a01:4f8:d16:1355::2 ~all"

Solution 2

Yes it is possible and it works, a SPF with both ip6 & Ip4 would look like:

"v=spf1 ip4:XX.XX.XX.XX ip6:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX ~all"

You can also in both cases add a CIDR (basis: /32 for ipv4 & /128 for ipv6) after each address to authorize a network range rather than a host.

Comments

[Martijn]

Could you add an example to your post on how to merge them?

[Sander Steffann]

In this (simple) example the resulting record would be TXT "v=spf1 ip4:78.46.138.249 ip6:2a01:4f8:d16:1355::2 ~all"

[Jakob Alexander Eichler]

why did you reserve 8 fields for ipv6?

[Nicolas Guérinet]

IPv6 addresses are represented as eight groups of four hexadecimal digits with the groups being separated by colons, for example 2001:0db8:0000:0042:0000:8a2e:0370:7334

[baptx]

Note that it seems preferred to use "-all" instead of "~all": serverfault.com/questions/355511/…