I have my mail being delivered locally, and a copy being forwarded to gmail as an off site backup.

A client sent me a zip file with a small .exe file inside it.

It forwarded the email to gmail, but the client recieved this email back.

<myusername@gmail.com>: host gmail-smtp-in.l.google.com[66.249.83.27] said: 552
5.7.0 Illegal Attachment h35si1442267wxd (in reply to end of DATA command)

Is there anyway to get that to not send back to the client, and silently fail at delivering mail? Or is this a gmail issue?