Example
This example creates a virtual link using the defaults for all optional pa ramete rs.
Console(config-router)#network 10.4.0.0 0.255.255.0.0 area 10.4.0.0
Console(config-router)#area 10.4.0.0 virtual-link 10.4.3.254
Console(config-router)#
This example creates a virtual link using MD5 authentication.
Console(config-router)#network 10.4.0.0 0.255.255.0.0 area 10.4.0.0
Console(config-router)#area 10.4.0.0 virtual-link 10.4.3.254
message-digest-key 5 md5 ld83jdpq
Console(config-router)#
Related Commands
show ip ospf virtual-links (42-51)
ip ospf authentication
This command specifies the authentication type used for an interface. Enter this
command without any optional parameters to specify plain text (or simple pas sword )
authentication. Use the
no
form to restore the default of no authentication.
Syntax
ip ospf authentication
[
message-digest
|
null
]
no ip ospf authentication
• message-digest - Specifies message-dige st (MD5) auth entication .
• null - Indicates that no authentication is used.
Command Mode
Interface Configuration (VLAN)
Default Setting
No authentication
Command Usage
• Use authentication to prevent routers from inadve rtently joinin g an
unauthorized area. Configure routers in the same area with the same
password or key. All neighboring routers on t he sam e ne two rk wit h t he s ame
password will exchange routing data.
• This command creates a password (key) that is insert ed into the OSPF
header when routing protocol packets are originated by this de vice. Ass ign a
separate password to each network for different interfaces.
• When using simple password authentication, a pa ssword is includ ed in the
packet. If it does not match the password configured on the re ceiving ro uter,
the packet is discarded. This method provides ver y little sec urity as it is
possible to learn the authentication key by snooping on rout ing protoco l
packets.
• When using Message-Digest 5 (MD5) authentication, the router uses the MD5
algorithm to verify data integrity by creating a 128-bit message digest from the
42-32
IP Routing Commands
42