You can use a spam filter to block emails by size.
**1.** Log in to your DirectAdmin Account.
**2.** In the **E-Mail Manager** section, click on **SPAM Filters**. Alternatively, type **SPAM Filters** in the **search bar**, and the option will appear. Click on it.
**3.** Under **Block By**, choose the **Size** option from the **drop-down** menu.
**4.** In **Value**, select the **size** in **KB** or **MB** and enter the value.
**5.** Click on **Block**.
If you have chosen size in MB and have entered the value 5, all emails exceeding 5MB in size will be blocked.