# Using CIDR notation to enter the IPv4 ACL mask

Use CIDR notation to enter ACL masks. The switch interprets the bits specified with CIDR notation as the address bits in an ACL and the corresponding address bits in a packet that must match. The switch then converts the mask to inverse notation for ACL use.

Address used in an ACL with CIDR notation |
Resulting ACL mask |
Meaning |
---|---|---|

10.38.240.125/15 |
0.1.255.255 |
The leftmost 15 bits must match; the remaining bits are wildcards. |

10.38.240.125/20 |
0.0.15.255 |
The leftmost 20 bits must match; the remaining bits are wildcards. |

10.38.240.125/21 |
0.0.7.255 |
The leftmost 21 bits must match; the remaining bits are wildcards. |

10.38.240.125/24 |
0.0.0.255 |
The leftmost 24 bits must match; the remaining bits are wildcards. |

18.38.240.125/32 |
0.0.0.0 |
All bits must match. |