use of EIGRP 'default-information out/in' command ?

[gowdakssujan]

use of EIGRP 'default-information out/in' command ?

[Giuseppe Larosa]

Hello @gowdakssujan ,

in first version of EIGRP it was possible to declare a default network .The router needed to be be:

in a diffferent major network (Class A, Class B, Class C based on first octect / byte)

advertised with a network command anf flagged with a flag bit.

Latest implementations do not honor this.

The interface command :

< ip eigrp 100 summary address 0.0.0.0 0.0.0.0 >

to send out and interface a default router in an EIGRP domain nedeed to tune the AD admin distance to avoid black hole in some cases.

So similarly to BGP and for advanced EIGRP applications lile Over the TOP a command like default -information out in

see

https://www.ciscopress.com/articles/article.asp?p=2999383&seqNum=3

for named mode

and

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_eigrp/command/ire-cr-book.pdf

This is your case:

default-information
>> To accept exterior or default routing information into Enhanced Interior Gateway Routing Protocol (EIGRP)
processes, use the default-information command in router configuration mode or address-family topology
configuration mode. To suppress exterior or default routing information in inbound or outbound updates, use
the no form of this command.
default-information {allowed {in | out} | in | out} [{acl-numberacl-name}]
no default-information {allowed {in | out} | in | out}
Cisco IOS Release 15.0(1)M, 12.2(33)SRE, 12.2(33)XNE, Cisco IOS XE Release 2.5 and Later Releases
default-information {in | out} [{acl-numberacl-name}]
no default-information {in | out} [{acl-numberacl-name}]

Hope to help

Giuseppe

[paul driver]

Hello
Is you question regarding eigrp default route advertisement, if so advertising a default is default in eigrp can be done a couple of ways:

1-redistribution of a default static 
2 -interface summary
3- ip network/candidate default route

Candidate default routes provide a gateway of last resort for routers/switches (basically a default route).
eigrp default-information is a way of sending/receiving specific candidate routes

Example1 - advertise multiple candidate routes – classful networks
R1 
ip default-network  1.0.0.0
ip default-network  2.0.0.0
ip default-network  3.0.0.0

router eigrp 1
network 1.1.1.1 0.0.0.0
network 2.1.1.1 0.0.0.0
network 3.1.1.1 0.0.0.0


r2-  receive all candidates routes however make 1.1.1.0/8 candidate default

access-list 10 permit 1.0.0.0 0.255.255.255
router eigrp 1
default-information in 10

Example2 - send all candidate routes but specify 2.0.0.0/8 as specific candidate default
rtr1 
ip default-network  1.0.0.0
ip default-network  2.0.0.0
ip default-network  3.0.0.0

router eigrp 1
network 1.1.1.1 0.0.0.0
network 2.1.1.1 0.0.0.0
network 3.1.1.1 0.0.0.0

access-list 10 permit 2.0.0.0 0.255.255.255
router eigrp 1
default-information out 10