Unnumbered IP examples

Last Updated : May 08, 2023 |
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In the following example, a VLAN interface is configured, and then the Dialer interface is configured with an unnumbered IP address, borrowing the IP address from the VLAN interface.
//enter the context of vlan interface 1:
Gxxx-001(super)# interface Vlan 1
//to configure the IP address of the vlan interface:
Gxxx-001(super-if:Vlan 1)# ip address 180.0.0.1 255.255.255.0
Gxxx-001(super-if:Vlan 1)# exit
Gxxx-001# !
//enter the context of the Dialer interface:
Gxxx-001(super)# interface dialer 1
Gxxx-001(super-if:Dialer 1)# dialer string 1 3001
Gxxx-001(super-if:Dialer 1)# dialer persistent delay 1
Gxxx-001(super-if:Dialer 1)# dialer modem-interface USB-modem
//to configure IP unnumbered on the Dialer interface, borrowing the IP address from vlan interface 1, configured above:
Gxxx-001(super-if:Dialer 1)# ip unnumbered 1 Vlan 1
Gxxx-001(super-if:Dialer 1)# exit
Gxxx-001(super)# !
The following sample routing table shows how routes discovered on unnumbered interfaces by routing protocols are listed as via routes in the Next-Hop column:
Network
Mask
Interface
Next-Hop
Cost
TTL
Source
-----------
-----
-------------
---------------
--------
-----
---------
0.0.0.0
0
FastEth10/3
149.49.54.1
1
n/a
STAT-HI
2.2.2.0
24
Vlan15
2.2.2.1
1
n/a
LOCAL
10.0.0.0
8
Vlan1
0.0.0.40
1
n/a
LOCAL
3.0.0.0
8
Tunnel1
Via Dia.1
2
172
RIP
4.0.0.0
8
Tunnel 1
Via Dia.1
2
172
RIP
20.0.0.0
8
Tunnel 1
Via Dia.1
11112
n/a
OSPF
20.0.0.1
32
Tunnel 1
Via Dia.1
22222
n/a
OSPF
26.0.0.0
8
Vlan 15
2.2.2.2
3
n/a
STAT-LO
99.0.0.0
8
Vlan 99
99.1.1.1
1
n/a
LOCAL
135.64.0.0
16
FastEth 10/3
149.49.54.1
1
n/a
STAT-HI
149.49.54.0
24
FastEth 10/3
149.49.54.112
1
n/a
LOCAL
180.0.0.0
8
Loopback 1
180.0.0.1
1
n/a
LOCAL
Related links
Unnumbered IP interfaces