Field MaximumVerifiedSignaturesPerMessage

Namespace

MailFathom.Domain.Emails.Authentication

Assembly

MailFathom.Domain.dll

How many of a message's DKIM signatures are verified before the rest are passed over.

public const int MaximumVerifiedSignaturesPerMessage = 8

Returns

int

How many of a message's DKIM signatures are verified before the rest are passed over.

Remarks

Each signature costs a key lookup, so an attacker writing hundreds of them into one message would otherwise buy hundreds of DNS queries per delivery from a mailbox that has to parse whatever arrives. Ordinary mail carries one or two — an author's and a delivery provider's — so the bound is far above what a legitimate message uses and far below what one would cost.