Using the default-information arise Command
OSPF does not abutment redistribution of statically authentic absence routes. Instead, OSPF requires
the default-information arise router subcommand, which about tells OSPF to
redistribute any absence routes activate in the acquisition table, either changeless routes or routes from another
routing protocol. The afterward account summarizes the absence acquisition appearance back application the
default-information arise command with OSPF:
■ Redistributes any absence avenue (0.0.0.0/0) in the acquisition table.
■ The command can set the metric and metric blazon directly, with OSPF behind to amount 1 and
type E2.
■ OSPF allows the use of the consistently keyword, which agency a absence is sourced behindhand of
whether a absence avenue is in the acquisition table.
■ Not accurate by EIGRP.
■ Accurate by RIP, with some differences. (Refer to the argument afterward Archetype 10-9 for an
explanation of the differences.)
Example 10-9 shows an archetype of application the default-information arise command with
OSPF. In this case, R1 has abstruse a avenue to 0.0.0.0/0 via BGP from R9 in Figure 10-8.
As mentioned earlier, RIP does abutment the default-information arise command; however,
the command behaves hardly abnormally in RIP than it does in OSPF. With RIP, this command
creates and advertises a absence avenue if either no absence avenue exists or a absence avenue was learned
from addition acquisition protocol. However, if a changeless avenue to 0.0.0.0/0 is in the bounded acquisition table,
the default-information arise command does not account RIP to inject a default—the reason
behind this behavior is that RIP already supports redistribution of changeless routes, so redistribute
static should be acclimated in that case.
Static Absence Avenue with Avenue Redistribution
router ospf 1
network 15.0.0.0 0.255.255.255 breadth 0
default-information originate
! R5 has a absence route, behind to blazon E2, amount 1. It as advertised as a
! blazon 5 LSA.
R5# appearance ip avenue ospf
O*E2 0.0.0.0/0 [110/1] via 15.1.1.1, 00:18:07, Serial0/0.1
R5# sh ip ospf abstracts | activate Type-5
Type-5 AS External Link States
Link ID ADV Router Age Seq# Checksum Tag
0.0.0.0 1.1.1.1 1257 0x80000001 0x008C12 1