On 10.09.2024 14:59 Faisal Misle via mailop wrote: > The host in question is: `spf.savea.se` which has the following > mechanism "ip6:0:0:0:0:0:ffff:5b6a:c61d"
This part is faulty because it is not a GUA address (2000::/3). IPv4-mapped is for sockets (represent v4 addr in v6 sockets, so only v6 sockets are needed) on a machine and not for any real communication outside of that machine. Such addresses must not appear on the internet and are therefore useless in the SPF. In the internet only addresses of 2000::/3 can be used for communication. Even when you can place other address types in the SPF, they are useless because they can't be used anyway for communication. > A couple of SPF validators throw different sets of warnings: > - The address 0:0:0:0:0:ffff:5b6a:c61d is not a valid IPv6 address. > Please correct the address and try again. > - (WARNING: non-routable IP-address: IPv4-mapped addresses). Exactly the latter is true. > I've tried researching but haven't been able to find a good example to > pass along to the powers that be on why that mechanism should not be > in that SPF record. Any pointers or links to relevant tech docs would > be appreciated! https://www.rfc-editor.org/rfc/rfc4291 https://www.ibm.com/docs/en/zos/2.1.0?topic=addresses-ipv4-mapped-ipv6 _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
