---
name: "firehol-mac"
section: "5"
platform: "linux"
package: "firehol-doc"
version: "3.1.8+ds-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/firehol-mac"
---

# firehol-mac(5)

ensure source IP and source MAC address match

## NAME

firehol-mac - ensure source IP and source MAC address match

## SYNOPSIS

mac *IP* *macaddr*

## DESCRIPTION

Any `mac` commands will affect all traffic destined for the firewall host, or to be forwarded by the host. They must be declared before the first router or interface.

**Note**

There is also a `mac` parameter which allows matching MAC addresses within individual rules (see [firehol-params(5)](/firehol-params/5.md)).

The `mac` helper command DROPs traffic from the *IP* address that was not sent using the *macaddr* specified.

When packets are dropped, a log is produced with the label “MAC MISSMATCH” (sic.). `mac` obeys the default log limits (see \[LOGGING\]\[\] in [firehol-params(5)](/firehol-params/5.md)).

**Note**

This command restricts an IP to a particular MAC address. The same MAC address is permitted send traffic with a different IP.

## EXAMPLES

-

  ```
  mac 192.0.2.1    00:01:01:00:00:e6
  mac 198.51.100.1 00:01:01:02:aa:e8
  ```

## SEE ALSO

- •

  [firehol(1)](/firehol/1.md) - FireHOL program

- •

  [firehol.conf(5)](/firehol.conf/5.md) - FireHOL configuration

- •

  [firehol-params(5)](/firehol-params/5.md) - optional rule parameters

- •

  FireHOL Website ⟨http://firehol.org/⟩\\c

- •

  FireHOL Online PDF Manual ⟨http://firehol.org/firehol-manual.pdf⟩\\c

- •

  FireHOL Online Documentation ⟨http://firehol.org/documentation/⟩\\c

## AUTHORS

FireHOL Team.