I have a suspicion that somebody is sending spam from my domain. Today I received an email from postmaster(
AT)halliburton.com to htuwxjw(
AT)example.com which said:
The following email was blocked because it contained an attached file type that is prohibited by the Halliburton email gateway:
Subject: ATTN: Important notification for a Visa / MasterCard holder!
AT)example.com does not exist. I have a catch-all email which receives any email sent to @example.com.
Is there anything I can do to prevent this? I have this TXT record on example.com: (MX records are Google's)
v=spf1 a mx ?all
I'm worried that any emails I send will be blacklisted if this person keeps sending emails as if they're from my domain.