3com 3031 Instruccion De Instalación

For each interface of a router, multiple IP addresses can be configured, among 
which one is the master IP address and the rest are slave IP addresses. In the 
interface view, the following commands can be used to modify the master IP 
address of the interface and the subnet mask.

Use a mask 

net-mask

 to identify the network ID contained in an IP address. 

Example: the IP address of an Ethernet interface of a router is 129.9.30.42, and 
the mask is 255.255.0.0. Logic AND the IP address with the mask, the network ID 
of the router's Ethernet interface will be given out: 129.9.0.0.

When configuring a master IP address, if an IP address has already been 
configured on the interface, the original master IP address will be replaced by the 
new one.

An interface can have only one master IP address. When deleting IP addresses of 
an interface, if no IP address is specified, then all its IP addresses (including all slave 
IP addresses) are deleted, otherwise only the specified IP address is deleted.

When there is at least one slave IP address, the master IP address cannot be 
deleted. Before the master IP address is deleted, all the slave IP addresses must be 
deleted.

Besides the master IP address, several slave IP addresses can be configured on an 
interface. The purpose of assigning slave IP addresses is to have the same interface 
located in different sub-nets, so as to create network routes with the same 
interface as the output port, and set up connection via the same interface to 
multiple sub-nets.

If no IP address is specified while using the delete command, all the IP addresses of 
the interface will be deleted.

When an interface is encapsulated with PPP, but not configured with IP address, 
perform the following task to configure the negotiable attribute of IP address for 
this interface (configuring the

 command on local 

router while configuring the

 command on the peer router), so 

that the local interface can accept the IP address originated from PPP negotiation. 

Table 404   Configuring master IP address of an interface

Configuring master IP address of an 
interface

Delete IP address of an interface

undo ip address [ ip-address net-mask ]

Table 405   Configuring slave IP address of an interface

Configuring slave IP address of an interface

ip address ip-address net-mask sub

Delete slave IP address of an interface

undo ip address [ ip-address 
net-mask [sub] ]