Cisco WS-C2980G-A Software Guide - Page 51

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Chapter 3 Configuring the Switch IP Address and Default Gateway Configuring Default Gateways Note In some cases, you might want to configure static IP routes in addition to default gateways. For information on configuring static routes, see the "Configuring Static Routes" section on page 27-9. You can define up to three default IP gateways. Use the primary keyword to make a gateway the primary gateway. If you do not specify a primary default gateway, the first gateway that is configured is the primary gateway. If more than one gateway is designated as primary, the last primary gateway that is configured is the primary default gateway. The switch sends all off-network IP traffic to the primary default gateway. If connectivity to the primary gateway is lost, the switch attempts to use the backup gateways in the order they were configured. The switch sends periodic ping messages to determine whether each default gateway is up or down. If connectivity to the primary gateway is restored, the switch resumes sending traffic to the primary. If both the in-band (sc0) and management Ethernet (me1) interfaces are configured when you specify default gateways, then the switch software automatically determines through which interface each default gateway can be reached. To specify one or more default gateways, perform this task in privileged mode: Step 1 Step 2 Step 3 Task Command Configure a default IP gateway address for the set ip route default gateway [metric] [primary] switch. (Optional) Configure additional default gateways set ip route default gateway [metric] [primary] for the switch. Verify that the default gateways appear correctly show ip route in the IP routing table. To remove default gateway entries, perform one of these tasks in privileged mode: Task Clear an individual default gateway entry. Clear all default gateways and static routes. Command clear ip route default gateway clear ip route all This example shows how to configure three default gateways on the switch and how to verify the default gateway configuration: Console> (enable) set ip route default 10.1.1.10 Route added. Console> (enable) set ip route default 10.1.1.20 Route added. Console> (enable) set ip route default 10.1.1.1 primary Route added. Console> (enable) show ip route Fragmentation Redirect Unreachable enabled enabled enabled The primary gateway: 10.1.1.1 Destination Gateway default 10.1.1.1 default 10.1.1.20 RouteMask ---------0x0 0x0 Flags ----UG G Use -------6 0 Interface --------- sc0 sc0 78-15486-01 Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide-Release 8.1 3-7

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3-7
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide
Release 8.1
78-15486-01
Chapter 3
Configuring the Switch IP Address and Default Gateway
Configuring Default Gateways
Note
In some cases, you might want to configure static IP routes in addition to default gateways. For
information on configuring static routes, see the
“Configuring Static Routes” section on page 27-9
.
You can define up to three default IP gateways. Use the
primary
keyword to make a gateway the primary
gateway. If you do not specify a primary default gateway, the first gateway that is configured is the
primary gateway. If more than one gateway is designated as primary, the last primary gateway that is
configured is the primary default gateway.
The switch sends all off-network IP traffic to the primary default gateway. If connectivity to the primary
gateway is lost, the switch attempts to use the backup gateways in the order they were configured. The
switch sends periodic ping messages to determine whether each default gateway is up or down. If
connectivity to the primary gateway is restored, the switch resumes sending traffic to the primary.
If both the in-band (sc0) and management Ethernet (me1) interfaces are configured when you specify
default gateways, then the switch software automatically determines through which interface each
default gateway can be reached.
To specify one or more default gateways, perform this task in privileged mode:
To remove default gateway entries, perform one of these tasks in privileged mode:
This example shows how to configure three default gateways on the switch and how to verify the default
gateway configuration:
Console> (enable)
set ip route default 10.1.1.10
Route added.
Console> (enable)
set ip route default 10.1.1.20
Route added.
Console> (enable)
set ip route default 10.1.1.1 primary
Route added.
Console> (enable)
show ip route
Fragmentation
Redirect
Unreachable
-------------
--------
-----------
enabled
enabled
enabled
The primary gateway: 10.1.1.1
Destination
Gateway
RouteMask
Flags
Use
Interface
---------------
---------------
----------
-----
--------
---------
default
10.1.1.1
0x0
UG
6
sc0
default
10.1.1.20
0x0
G
0
sc0
Task
Command
Step 1
Configure a default IP gateway address for the
switch.
set ip route
default
gateway
[
metric
] [
primary
]
Step 2
(Optional) Configure additional default gateways
for the switch.
set ip route
default
gateway
[
metric
] [
primary
]
Step 3
Verify that the default gateways appear correctly
in the IP routing table.
show ip route
Task
Command
Clear an individual default gateway entry.
clear ip route
default
gateway
Clear all default gateways and static routes.
clear ip route
all