EIGRP and no auto-summary

[ksohan4730]

Hi Guys,

Even though i've configured the no auto-summary command under router eigrp XXX, it doesn't show up when i do a sh run.

I also have it configured under the bgp AS and it shows up there, but not under the eigrp process

Any reason for that?

router eigrp XXX
network x.x.x.x x.x.x.x

passive-interface default
no passive-interface Port-channel1
no passive-interface Loopback0

[Peter Paluch · Accepted solution]

Hi,

Please issue the show ip protocols command and in its output, locate the section related to EIGRP, and within this section, look for the line

Automatic network summarization is not in effect

If this line is present then the auto-summary is indeed deactivated. It is probable that this has become default in the most recent versions of IOS.

Best regards,

Peter

[Kishore Chennupati · Accepted solution]

Hi,

Peter is right.

Here is an excerpt from Cisco  command reference guide from the following link

http://www.cisco.com/en/US/docs/ios/iproute_eigrp/command/reference/ire_a1.html#wp1062919

Cisco IOS Release 15.0(1)M, 12.2(33)SRE, 12.2(33)XNE, Cisco IOS XE

Release 2.5, Cisco IOS Release 12.2(33)SXI4 and Later Releases

The behavior of this command is disabled by default (the software sends subprefix routing information across classful network boundaries).

The key take away here is that almost all, if not all, versions of 15, and the newest versions of 12.2(33) (primarily used in IOS switches - i.e. 6500's) now have auto summary disabled by default. This means all IOS devices running 15 code will not have the "no auto-summary" statement in their running-configs because it's already there. So, when you start rolling out new versions of code, expect to see your EIGRP config change to something that looks similar to this:

router eigrp 100
network 10.0.0.0

HTH,

Regards,

Please rte if helpful

[ksohan4730]

You guys are right, i checked and its indeed disabled...

I also checked several other devices where i noticed the same issue and the IOS are fairly new on those devices.

1) Version 15.1(2)T2

2) Version 12.2(55)SE

Thanks for the feeback, wonderful job.