[Chapter 12] 12.3 Things to Try
Author: Bryan Costales & Eric Allman
Date: 1999-01-06T18:37:01Z

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| Chapter 12 Class |

## 12.3 Things to Try

- In an `F` command, rather than specifying the name of a file, specify the name of a directory or a device such as /dev/null. Does sendmail care? How does it handle (or not handle) nonfiles?

- Use /usr/dict/words as a class file. Does reading a huge file slow sendmail down noticeably? Does this suggest that a database might be more efficient for some needs?

- Are there security concerns surrounding use of the `F` command? Imagine ways in which a cracker might exploit a careless use of the `F` command to compromise your system. Skip ahead to Section 22.4.2, "The F Command - File Form" to explore this question further.

12.2 The File Form of Class |  | 13. Setting Options