IP configuration features

IP configuration features:

Feature

Default

IP Address and Subnet Mask

DHCP/Bootp

Multiple IP Addresses on a VLAN

n/a

Default Gateway Address

none

Packet Time-To-Live (TTL)

64 seconds

Time Server (Timep)1

DHCP

Single Source IP Addressing

outgoing IP address

1

For more on this topic, see the "Time Protocols" chapter in the latest Management and Configuration Guide.

IP address and subnet mask. Configuring the switch with an IP address expands your ability to manage the switch and use its features. By default, the switch is configured to automatically receive IP addressing on the default VLAN from a DHCP/Bootp server that has been configured correctly with information to support the switch. (See DHCP/Bootp operation for information on setting up automatic configuration from a server.) However, if you are not using a DHCP/Bootp server to configure IP addressing, use the menu interface or the CLI to manually configure the initial IP values. After you have network access to a device, you can use the WebAgent to modify the initial IP configuration if needed.

For information on how IP addressing affects switch operation, See Effects of IP addressing on switch operation.

Multinetting: assigning multiple IP addresses to a VLAN. For a given VLAN you can assign up to 32 IP addresses. This allows you to combine two or more subnets on the same VLAN, which enables devices in the combined subnets to communicate normally through the network without needing to reconfigure the IP addressing in any of the combined subnets.

Default gateway operation. The default gateway is required when a router is needed for tasks such as reaching off-subnet destinations or forwarding traffic across multiple VLANs. The gateway value is the IP address of the next-hop gateway node for the switch, which is used if the requested destination address is not on a local subnet/VLAN. If the switch does not have a manually-configured default gateway and DHCP/Bootp is configured on the primary VLAN, then the default gateway value provided by the DHCP or Bootp server will be used. If the switch has a manually configured default gateway, then the switch uses his gateway, even if a different gateway is received via DHCP or Bootp on the primary VLAN. This is also true for manually configured TimeP, SNTP, and Time-To-Live(TTL). (In the default configuration, VLAN 1 is the Primary VLAN.)

For more information on Primary VLANs, see the Advanced Traffic Management Guide.

For more information on TimeP and SNTP, see the “Time Protocols” chapter in the Management and Configuration Guide.

Packet Time-To-Live (TTL). This parameter specifies the maximum number of routers (hops) through which a packet can pass before being discarded. Each router decreases a packet’s TTL by 1 before forwarding the packet. If decreasing the TTL causes the TTL to be 0, the router drops the packet instead of forwarding it. In most cases, the default setting (64) is adequate.