Cisco Catalyst 6500 Series User Manual

D-3
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide
OL-6392-01
Appendix D Addresses, Protocols, and Ports Reference
IP Addresses and Subnet Masks
Determining the Subnet Mask
To determine the subnet mask based on how many hosts you want, see Table D-1.
Determining the Address to Use with the Subnet Mask
The following sections describe how to determine the network address to use with a subnet mask for a
Class C-size and a Class B-size network:
• Class C-Size Network Address, page D-4
• Class B-Size Network Address, page D-4
Table D-1 Hosts, Bits, and Dotted Decimal Masks
Hosts
1
1. The first and last number of a subnet are reserved, except for /32, which identifies a single host.
/Bits Mask Dotted Decimal Mask
16,777,216 /8 255.0.0.0 Class A Network
65,536 /16 255.255.0.0 Class B Network
32,768 /17 255.255.128.0
16,384 /18 255.255.192.0
8,192 /19 255.255.224.0
4,096 /20 255.255.240.0
2,048 /21 255.255.248.0
1,024 /22 255.255.252.0
512 /23 255.255.254.0
256 /24 255.255.255.0 Class C Network
128 /25 255.255.255.128
64 /26 255.255.255.192
32 /27 255.255.255.224
16 /28 255.255.255.240
8 /29 255.255.255.248
4 /30 255.255.255.252
Do not use /31 255.255.255.254
1 /32 255.255.255.255 Single Host Address

Cisco Catalyst 6500 Series Specifications

General

Brand	Cisco
Model	Catalyst 6500 Series
Category	Switch
Language	English