DNS SPF settings to reduce backscatter to catchall address from spoofed emails

[cantoris]

I use the mail.btinternet.com outbound server to send messages from name@mydomain.co.uk.

Spammers are sending messages, spoofing the from address as random@mydomain.co.uk

These spam messages bounce back to my catchall account as undeliverable.

I want to set a SPF type DNS record to help mail servers distinguish between genuine mail from me and spoofed mail from spammers.

Can anyone advise what that SPF record should contain, to allow mail.btinternet.com and exclude others?

Many thanks for any help,

  Nigel.

[Oliver341]

Unfortunately you cannot do this because there is no published spf record for btinternet.com

[cantoris]

Thank you. But do I actually need such a record? I'm hoping I can modify the SPF record for mydomain.co.uk to include permission to use the btmail server, which is something like ...cpcloud.co.uk.

  Nigel.

[Oliver341]

You don't need an SPF record, but it is preferable. In this instance however, it's not possible.

[cantoris]

Thanks for the advice (I've been away a while). Backscatter is still a problem so I'll look for another solution.