Domain sub domain under primary domain

[kapildev]

Need help to Block sender sub domain under primary domain - 

Example; @*.abc.com , where * is wildcard subdomain.

[Ken Stieers]

So to start, if you dont have a "block everything" Incoming mail policy, build that.

It should be your first one in the list. Disable all scanning, AV etc. Create one incoming content filter, with no conditions, one action to drop everything, and enable it for just this policy.

In this "block everything" policy, add a sender as "@.baddomain.com"

[kapildev]

so if I do that it will block email coming from domain like; @a.abc.com or @b.abc.com or @c.abc.com or @x.abc.com ......

[Ken Stieers]

Yes. The @.domain.tld matches all of the subdomains.