[Igor M]

After some lab testing (using IOS 12.4/12.4T on C2811 and C3745) I'm led
to believe that the command

distance <distance> <ip-address> <wildcard-mask> [ip-standard-acl |
ip-extended-acl | access-list-name]

applied in "router eigrp" works only for EIGRP-internal routes.
EIGRP-external routes always get the default EIGRP admin distance for
external routes, no matter if they match an ACL or neighbor IP in the
distance command.

However, I can't seem to find this behavior to be documented anywhere
(at least not in IOS 12.4 Config Guide or Command Reference Guide).

Can anyone shed light on this - is this by design, and if so, is there a
way to selectively apply AD values to external EIGRP routes?

I am aware of of the "distance eigrp" command, but this is not an
option, since I need to alter admin distance for specific external
routes only.

[raaki_88]

hello igor m .. although my reply may match or may not match your standard/query iam trying ..

there is way where in we can change the default administrative distance in eigp summary address ....

routera(config-if)#ip summary-address eigrp 172.16.0.0 255.255.248.0 ?
<1-255> administrative distance

its default left to 5 how ever ... i found this

regards
raaki

12.4

[earl]

raaki_88, on Sep 23 2008, 10:11 AM, said:

hello igor m .. although my reply may match or may not match your standard/query iam trying ..

there is way where in we can change the default administrative distance in eigp summary address ....

routera(config-if)#ip summary-address eigrp 172.16.0.0 255.255.248.0 ?
<1-255> administrative distance

its default left to 5 how ever ... i found this

regards
raaki

12.4

i think the AS should be included.

Router(config-if)#ip summary-address eigrp ?
<1-65535> Autonomous system number


Router(config-if)#ip summary-address eigrp 1 1.0.0.0 255.0.0.0 ?
<1-255> Administrative distance
leak-map Allow dynamic prefixes based on the leak-map
<cr>

regards,
earl

[ManishBehal]

But how will you so it for selective routes, that are outside that boundary? Example being change the dstance for prefixes:-

128.128.2.0/24
172.12.19./24
200.204.220.0/24
15.3.0.0/16

These are (some) coming in from OSPF via mutual redistribution. I want these to be changed and everything else to remain the same.

[Igor M]

Well, this is precisely the question I sumbled upon - my question required me not to use route maps in a two-point ospf<->eigrp redistribution and yet make some of my external eigrp routes preferred over the same ones leaking through ospf and back into eigrp...

ManishBehal, on Sep 23 2008, 02:13 AM, said:

But how will you so it for selective routes, that are outside that boundary? Example being change the dstance for prefixes:-

128.128.2.0/24
172.12.19./24
200.204.220.0/24
15.3.0.0/16

These are (some) coming in from OSPF via mutual redistribution. I want these to be changed and everything else to remain the same.

[ManishBehal]

And that Igor my friend the question I threw back to the other posters thatn suggested summarizing at the boundary. The ip summary address is far to fixed for this type of question as it does not meet the requirements of your question fully.

Life's bad.

[ravy2005]

Hi Igor,

Are you trying to load balance between two routers that are mutually re-distributing between EIGRP and OSPF however the network off of one is being preferred? If so then you will need to increase the AD of OSPF routes to > 170 (EIGRP External) and then it will load balance.

HTH

Ravi

[Igor M]

Since i could not make this work under eigrp, I turned to ospf for the same command functionality. Ospf does allow for changing ad of selective external routes, however the 'source ip' puzzles me even more - the only source that works for me is the '0.0.0.0 255.255.255.255'.
Here is my simple setup :


R3-R2-R5-R3
R3 pulls the '178xxx' routes from external bb.
R3 and R2 run both eigrp and ospf, R5 runs ospf only. R2 and R3 do 2-way redistribution. R5 s0/0 is 100.1.1.5, and R5 RID: 100.100.5.5

I need to make R2 take these routes from eigrp:

O E2	178.2.1.0 [110/20] via 100.1.1.5, 00:04:52, Serial1/0.1
O E2	178.2.3.0 [110/20] via 100.1.1.5, 00:04:52, Serial1/0.1
O E2	178.2.5.0 [110/20] via 100.1.1.5, 00:04:52, Serial1/0.1

Distance under eigrp did not work, so under ospf the two distance commands do not make the change:

 distance 171 100.1.1.5 0.0.0.0 ACL
 distance 171 100.100.5.5 0.0.0.0 ACL

The only one that works is the 'distance 171 0.0.0.0 255.255.255.255 ACL', which now makes my eigrp preferrable

R2#sh ip route | i 178
	 178.2.0.0/24 is subnetted, 3 subnets
D EX	178.2.1.0 [170/2323456] via 100.1.1.34, 00:00:09, Serial1/0.2
D EX	178.2.3.0 [170/2323456] via 100.1.1.34, 00:00:09, Serial1/0.2
D EX	178.2.5.0 [170/2323456] via 100.1.1.34, 00:00:09, Serial1/0.2

Anyone has any comments on why the ospf distance does not like the specific source?

ManishBehal, on Sep 23 2008, 08:43 AM, said:

And that Igor my friend the question I threw back to the other posters thatn suggested summarizing at the boundary. The ip summary address is far to fixed for this type of question as it does not meet the requirements of your question fully.

Life's bad.

[Igor M]

I got it...

Here:

R2#sh ip ospf database | i 178
178.2.1.0 100.100.3.3 58 0x80000001 0x00DF3C 0
178.2.3.0 100.100.3.3 58 0x80000001 0x00C950 0
178.2.5.0 100.100.3.3 58 0x80000001 0x00B364 0

R2#sh ip route | i 178
178.2.0.0/24 is subnetted, 3 subnets
O E2 178.2.1.0 [110/20] via 100.1.1.5, 00:00:00, Serial1/0.1
O E2 178.2.3.0 [110/20] via 100.1.1.5, 00:00:00, Serial1/0.1
O E2 178.2.5.0 [110/20] via 100.1.1.5, 00:00:00, Serial1/0.1

Which means the database was sourced from R3, even though next-hop points to R5...
I guess the database instance gets installed from a router that is hop-closer to that bunch of networks... Gotta be extra cautious with this...

Thanks guys

Igor M, on Sep 23 2008, 09:31 AM, said:

Since i could not make this work under eigrp, I turned to ospf for the same command functionality. Ospf does allow for changing ad of selective external routes, however the 'source ip' puzzles me even more - the only source that works for me is the '0.0.0.0 255.255.255.255'.
Here is my simple setup :


R3-R2-R5-R3
R3 pulls the '178xxx' routes from external bb.
R3 and R2 run both eigrp and ospf, R5 runs ospf only. R2 and R3 do 2-way redistribution. R5 s0/0 is 100.1.1.5, and R5 RID: 100.100.5.5

I need to make R2 take these routes from eigrp:

O E2	178.2.1.0 [110/20] via 100.1.1.5, 00:04:52, Serial1/0.1
O E2	178.2.3.0 [110/20] via 100.1.1.5, 00:04:52, Serial1/0.1
O E2	178.2.5.0 [110/20] via 100.1.1.5, 00:04:52, Serial1/0.1

Distance under eigrp did not work, so under ospf the two distance commands do not make the change:

 distance 171 100.1.1.5 0.0.0.0 ACL
 distance 171 100.100.5.5 0.0.0.0 ACL

The only one that works is the 'distance 171 0.0.0.0 255.255.255.255 ACL', which now makes my eigrp preferrable

R2#sh ip route | i 178
	 178.2.0.0/24 is subnetted, 3 subnets
D EX	178.2.1.0 [170/2323456] via 100.1.1.34, 00:00:09, Serial1/0.2
D EX	178.2.3.0 [170/2323456] via 100.1.1.34, 00:00:09, Serial1/0.2
D EX	178.2.5.0 [170/2323456] via 100.1.1.34, 00:00:09, Serial1/0.2

Anyone has any comments on why the ospf distance does not like the specific source?

ManishBehal, on Sep 23 2008, 08:43 AM, said:

And that Igor my friend the question I threw back to the other posters thatn suggested summarizing at the boundary. The ip summary address is far to fixed for this type of question as it does not meet the requirements of your question fully.

Life's bad.

[DarkFiber]

Dear all,

FOR EIGRP
If it is an internal route, you can change thier AD , use the cmd "distance <AD> <source> <list>"
if it is an EIGRP external route you cannot do that per route, you can do this for all the external routes.
use the command "distance eigrp <internal_AD> <external_AD>"

conf t
router eigrp #
distance eigrp <internal_AD> <external_AD>
distance 200 <source> <ACL for internal networks> ( this overides the internal distance configured for ONLY routes matched in the ACL)


For OSPF
With OPSF you can change the AD for all internal/external routes via the cmd distance ospf external/internal <AD>
Also yo may overide it with the cmd distance # 0.0.0.0 255.255.255 <ACL> for some specific routes


conf t
router ospf 10
distance ospf internal 120 ( for all internal routes)
distance ospf external 200 ( for all external routes)
distance 110 0.0.0.0 255.255.255.255 <ACL for specific routes> ( overide any ospf distance cmds, used to manipulate any kind of routes that match in the ACL)


You may use this with Tags to elliminate any kind of routing loops

Hope it may help

This post has been edited by DarkFiber: 24 September 2008 - 01:05 PM

[FredBloggs]

DarkFiber, on Sep 24 2008, 04:03 AM, said:

Dear all,

FOR EIGRP
If it is an internal route, you can change thier AD , use the cmd "distance <AD> <source> <list>"
if it is an EIGRP external route you cannot do that per route, you can do this for all the external routes.
use the command "distance eigrp <internal_AD> <external_AD>"

conf t
router eigrp #
distance eigrp <internal_AD> <external_AD>
distance 200 <source> <ACL for internal networks> ( this overides the internal distance configured for ONLY routes matched in the ACL)


For OSPF
With OPSF you can change the AD for all internal/external routes via the cmd distance ospf external/internal <AD>
Also yo may overide it with the cmd distance # 0.0.0.0 255.255.255 <ACL> for some specific routes


conf t
router ospf 10
distance ospf internal 120 ( for all internal routes)
distance ospf external 200 ( for all external routes)
distance 110 0.0.0.0 255.255.255.255 <ACL for specific routes> ( overide any ospf distance cmds, used to manipulate any kind of routes that match in the ACL)


You may use this with Tags to elliminate any kind of routing loops

Hope it may help

Hey there DarkFiber,

Must have missed the post somewhere along the way but better late than never.....Congrats on the CCIE #

By the way, I like the forum ID. Never tried any Dark Fiber yet...time yet

[FredBloggs]

FredBloggs, on Sep 24 2008, 11:15 PM, said:

DarkFiber, on Sep 24 2008, 04:03 AM, said:

Dear all,

FOR EIGRP
If it is an internal route, you can change thier AD , use the cmd "distance <AD> <source> <list>"
if it is an EIGRP external route you cannot do that per route, you can do this for all the external routes.
use the command "distance eigrp <internal_AD> <external_AD>"

conf t
router eigrp #
distance eigrp <internal_AD> <external_AD>
distance 200 <source> <ACL for internal networks> ( this overides the internal distance configured for ONLY routes matched in the ACL)


For OSPF
With OPSF you can change the AD for all internal/external routes via the cmd distance ospf external/internal <AD>
Also yo may overide it with the cmd distance # 0.0.0.0 255.255.255 <ACL> for some specific routes


conf t
router ospf 10
distance ospf internal 120 ( for all internal routes)
distance ospf external 200 ( for all external routes)
distance 110 0.0.0.0 255.255.255.255 <ACL for specific routes> ( overide any ospf distance cmds, used to manipulate any kind of routes that match in the ACL)


You may use this with Tags to elliminate any kind of routing loops

Hope it may help

Hey there DarkFiber,

Must have missed the post somewhere along the way but better late than never.....Congrats on the CCIE #

By the way, I like the forum ID. Never tried any Dark Fiber yet...time yet

[DarkFiber]

Thanks : )

You may use this link

http://www.sadikhov....howtopic=137247 >>>>how i Passed exam

http://www.sadikhov....c=130250>>>>how to eliminate my silly mistakes that failed me before in the exam

[Igor M]

Just to recap on this one,
- if under eigrp on router receiving the redistributed [170] route you re-advertise the same route with a 'network' command, the route is brought back down to [90]. Nice find, thanks to Pick...

DarkFiber, on Sep 24 2008, 08:02 PM, said:

Thanks : )

You may use this link

http://www.sadikhov....howtopic=137247 >>>>how i Passed exam

http://www.sadikhov....c=130250>>>>how to eliminate my silly mistakes that failed me before in the exam

[DarkFiber]

Igor M, on Sep 25 2008, 04:00 PM, said:

Just to recap on this one,
- if under eigrp on router receiving the redistributed [170] route you re-advertise the same route with a 'network' command, the route is brought back down to [90]. Nice find, thanks to Pick...

DarkFiber, on Sep 24 2008, 08:02 PM, said:

Thanks : )

You may use this link

http://www.sadikhov....howtopic=137247 >>>>how i Passed exam

http://www.sadikhov....c=130250>>>>how to eliminate my silly mistakes that failed me before in the exam

Thats nice TIP IGOR , did you practise it , as i think if it works , it can be used in Traffic Engineering , i mean in changing traffic paths when using multiple IGP protocols + redistribution.

[Yuri Selivanov]

Igor M, on Sep 24 2008, 12:31 AM, said:

Since i could not make this work under eigrp, I turned to ospf for the same command functionality. Ospf does allow for changing ad of selective external routes, however the 'source ip' puzzles me even more - the only source that works for me is the '0.0.0.0 255.255.255.255'.
[snip]
Anyone has any comments on why the ospf distance does not like the specific source?
[snip]

When you're dealing w/ OSPF you have to specify *RID* of originating router. But for other beasts: RIP, EIGRP, IS-IS -- *src_addr*.

HTH!

[Igor M]

I concur, this trick works well. Nice fidgetry to keep handy in your arsenal.

Yuri Selivanov, on Sep 27 2008, 06:22 AM, said:

Igor M, on Sep 24 2008, 12:31 AM, said:

Since i could not make this work under eigrp, I turned to ospf for the same command functionality. Ospf does allow for changing ad of selective external routes, however the 'source ip' puzzles me even more - the only source that works for me is the '0.0.0.0 255.255.255.255'.
[snip]
Anyone has any comments on why the ospf distance does not like the specific source?
[snip]

When you're dealing w/ OSPF you have to specify *RID* of originating router. But for other beasts: RIP, EIGRP, IS-IS -- *src_addr*.

HTH!