[c-nsp] ospf (passive-interface default)

[Aaron]

Handy Lab ?!  You need GNS3.

As I understand it, that ...

router ospf 1
network 10.10.10.0 0.0.0.3 area 1

... will only run ospf hellos mcasted out interfaces that fall within that
range.... 10.10.10.0,  10.10.10.1, 10.10.10.2, 10.10.10.3... yes I believe
10.10.10.0 is possible too, according to some funky /31 thing that I heard
of a long time ago... yep, I just tried it in my .... ahhhrrm...  handy gns3
lab ;)

big-sp#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
big-sp(config)#int l 0
big-sp(config-if)#ip address 10.10.10.0 255.255.255.254 sec
% Warning: use /31 mask on non point-to-point interface cautiously
big-sp(config-if)#do sh run in l 0 | in ip address 10.10.10.0
 ip address 10.10.10.0 255.255.255.254 secondary

For more control you could also actually specify the exact ip address of the
interface... then you know it will only run on that interface...

Conf t
Int g1/0
Ip address 10.10.10.1 255.255.255.252

router ospf 1
network 10.10.10.1 0.0.0.0 area 1

....i tend to be very specific with that too.

There are cases where I know I want all interfaces to be in ospf , always,
even new interfaces and I don't want to have to specify anything else under
ospf for new interfaces...

Conf t
Router ospf 1
Network 0.0.0.0 255.255.255.255 area 0

BTW, incase you didn't know... Look how cool IOS XR is.... it actually does
it per interface AND nicely organized under the ospf construct

...kind of cool that you don't have to specify subnets and secondary
subnets... just advertises any and all subnets that are on the following
interfaces...

router ospf 1
 log adjacency changes
 router-id 10.101.0.6
 area 0.0.0.1
  passive enable
  interface Bundle-Ether1
   passive disable
  !
  interface Bundle-Ether2
   passive disable
  !
  interface Bundle-Ether3
   cost 1000
   passive disable
  !
  interface Loopback0
  !
  interface GigabitEthernet0/0/0/0
   passive disable
  !
  interface GigabitEthernet0/0/0/3
   cost 10000
   passive disable
  !
  interface BVI5


-----Original Message-----
From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of
CiscoNSP List
Sent: Tuesday, March 03, 2015 2:41 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] ospf (passive-interface default)

Hi Everyone,

Dont have a lab handy to test this, so hoping someone can answer:

If you configure:

router ospf 1
network 10.10.10.0 0.0.0.3 area 1

without passive-int default, will ospf be "enabled" on all Interfaces, or
just the Interface with 10.10.10.0/30 configured on it?

I was always under the impression that (best practice) is to do the
following, so that ospf is disabled on all ints, apart from the ones
configured with "no passive int foo"

router ospf 1
passive-int default
no passive int gi0/1
network 10.10.10.0 0.0.0.3 area 1

...and,  (As an alternative) is configuring ospf under each interface now a
method many use instead of the above example?

...I havent tried the "per int" method (I will later today), but in theory,
I think having all the config under "router ospf xx" would be easier to
maintain...i.e. all the config is in the one section for ospf?

Cheers.

 		 	   		  
_______________________________________________
cisco-nsp mailing list  cisco-nsp at puck.nether.net
https://puck.nether.net/mailman/listinfo/cisco-nsp
archive at http://puck.nether.net/pipermail/cisco-nsp/