check the link http://www.cisco.com/warp/public/105/default.html
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Aki Anttila
Sent: Thursday, January 04, 2001 12:59 PM
To: [EMAIL PROTECTED]
Subject: Re: ip route 0.0.0.0 V.S. ip default-network
Hi!
This may not answer your questions completely but hope it helps at least
somebody!
Originating the default routes for different routing protocols (not all...).
RIP and RIPv2
There are three possibilities:
1) If the RIP process has network 0.0.0.0 in its database, it will
distribute this as-is. No additional commands are needed.
2) However, with default-information originate, you can put RIP to advertise
a default route to all or certain interfaces, even if default does not
exist.
router rip
(version 2)
default-information originate route-map A
route-map A permit 10
set interface serial 0
3) If nothing else is configured ip default-network command can be given. If
the network specified in the command exist in the routing table then it
is considered as a default route.
IGRP and EIGRP
There are three possibilities:
1) Use ip default-network <classfull network>. This command flags this route
as default candidate and distributes it to neighbors. The same
applies to IGRP and EIGRP.
2) Use ip default-network <classless network>. This is much harder, since
IOS automatically makes a summary route out of the classless
network. Therefore, you need to have another ip default-network <summarized
classfull network> statement in order to get this working. Notice
also, that the default network MUST BE present in IGRP/EIGRP routing
process. It is not sufficient if it is just in the routers routing table!
3) If the default route (0.0.0.0/0) is already present in the routing table,
then it can be redistributed BUT only into the EIGRP process and the
process redistributes it to the neighbors. For IGRP, this cannot be done, so
the only and the best way is to use the ip default-network -command.
Notice also, that the flow of the default-information can be controlled by
the default-information originate -command.
OSPF
There are three possibilities:
1) Create a default route with ip route 0.0.0.0 0.0.0.0 1.2.3.4 -command.
Advertise this via OSPF with command default-information originate.
Notice also, that if you have ip default-network -command in the router,
then this is enough for OSPF to advertise default network.
2) Donīt create a static default. Advertise default with OSPF command
default-information originate always.
3) Have default network in some other process. Redistribute this into OSPF
process, which redistributes it to neighbors.
Remember that is you have OSPF NSSA areas, then the default route must be
advertised with area x nssa default-information originate-command.
Aki
""shanjun zou"" <[EMAIL PROTECTED]> wrote in message
9319g7$fhd$[EMAIL PROTECTED]">news:9319g7$fhd$[EMAIL PROTECTED]...
> Hi,every one
>
> when set the default route, is there any diffirence between ip route
0.0.0.0
> and ip default-network command? when will I use this one or another one ?
>
> thanks very much!
>
> ShanJun, zou
>
>
>
> _________________________________
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