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Appendix
This section discusses: Communities, Gateways, IP Addresses, and Sub net masking.
Communities
A community is a string of printable ASCII characters that identifies a user group with the same access privileges. For example, a common community name is “public.”
For security purposes, the SNMP agent validates requests before responding. The agent can be configured so that only trap managers that are members of a community can send requests and receive responses from a particular community. This prevents unauthorized managers from viewing or changing the configuration of a device.
Gateways
Gateway, also referred to as a router, is any computer with two or more network adapters connecting to different physical networks. Gateways allow for transmission of IP packets among networks on an Internet.
IP Addresses
Every device on an Internet must be assigned a unique IP (Internet Protocol) address. An IP address is a
IP addresses appear in dotted decimal (rather than in binary) notation. Dotted decimal notation divides the 32- bit value into four
To accommodate networks of different sizes, the IP address has three
Class | Value of First Octet | Network ID | Host ID | Number of Hosts |
A | First octet | Last three octets | 16,387,064 | |
B | First two octets | Last two octets | 64,516 | |
C | First three octets | Last octet | 254 |
Any value between 0 and 255 is valid as a host ID octet except for those values the InterNIC reserves for other purposes.
Value | Purpose |
0, 255 | Subnet masking |
127Loopback testing and interprocess communication on local devices
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