From: Jaeheon Yoo (kghost@xxxxxxxxxxxx)
Date: Sat Mar 02 2002 - 00:49:30 GMT-3
Hi, Tshon
What you posted by pasting from Cisco Documentation has a wrong statement.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/ip_r/ip
rprt2/1rdindep.htm#xtocid2
It says:
> In the following example, the set distance is from the least to the most
> specific network.
>
> router igrp 100
> network 10.0.0.0
> distance 22 10.0.0.0 ---> can't be configured!
> distance 33 10.11.0.0 0.0.255.255
> distance 44 10.11.12.0 0.0.0.255 ----> it has no effect at all!
>
> -----------------------------------------------------------------------------
--- > Note In this example, adding distance 255 to the end of the list > would override the distance values for all networks within the range > specified in the example. The result is that the distance values are set > to 255. > ----------------------------------------------------------------------------- ---This is totally wrong. 1) A distance command without a inverse mask can't be c onfigured. I guess it's because ip address(source)/inverse mask pair seems to b e used as a key index for distance commands in IOS internal code. 2) Distance c ommands are evaluated in the order they are configured, until there is a match statement. the distance commands after the match statement are never evaluated for the same matched source router. It's like ospf network statements.
Please look at this.
router igrp 1 network 172.16.0.0 distance 220 distance 120 172.16.0.0 0.0.255.255 ----> it covers all! distance 200 172.16.46.0 0.0.0.255 ---> it has no effect. distance 160 172.16.24.0 0.0.0.3 20 ---> no effect ! access-list 20 permit 172.16.26.0
Rack02R4#sh ip route 172.16.0.0/24 is subnetted, 6 subnets C 172.16.46.0 is directly connected, Serial0 C 172.16.24.0 is directly connected, Serial1 I 172.16.26.0 [120/8576] via 172.16.24.2, 00:00:04, Serial1 C 172.16.4.0 is directly connected, Loopback0 I 172.16.6.0 [120/8976] via 172.16.46.6, 00:00:05, Serial0 I 172.16.2.0 [120/8976] via 172.16.24.2, 00:00:04, Serial1 ------------------------------------------------------------------------------- -------
router igrp 1 network 172.16.0.0 distance 220 distance 200 172.16.46.0 0.0.0.255 distance 160 172.16.24.0 0.0.0.3 20 distance 240 172.16.0.0 0.0.255.255 ---> it has no effect at all. ! access-list 20 permit 172.16.26.0
Rack02R4#sh ip route 172.16.0.0/24 is subnetted, 6 subnets C 172.16.46.0 is directly connected, Serial0 C 172.16.24.0 is directly connected, Serial1 I 172.16.26.0 [160/8576] via 172.16.24.2, 00:00:05, Serial1 C 172.16.4.0 is directly connected, Loopback0 I 172.16.6.0 [200/8976] via 172.16.46.6, 00:00:04, Serial0 I 172.16.2.0 [220/8976] via 172.16.24.2, 00:00:05, Serial1
One more thing: 12.1(5)T10 on C2500 shows some buggy behavior when you configur e a distance command with an ACL. You have to add a space after ACL number!
("_" is where you press "Enter" key) Rack02R4(config-router)#distance 160 172.16.24.0 0.0.0.3 20_ % Invalid access list name. Rack02R4(config-router)#distance 160 172.16.24.0 0.0.0.3 20 _ Rack02R4(config-router)#^Z
Regards, Jaeheon
----- Original Message ----- From: "Tshon" <tshon@netzero.net> To: "ying chang" <ying_c@hotmail.com> Cc: <wade.edwards@powerupnetworks.com>; <ccielab@groupstudy.com> Sent: Saturday, March 02, 2002 8:55 AM Subject: Re: Manipulate administrative distance
> > I believe that this will help you. The thing to get is that if you want > to have several distance commands set they are placed in opposite order > of what you would do with and access list. > > > Numerically, an administrative distance is an integer between 0 and 255. > In general, the higher the value, the lower the trust rating. An > administrative distance of 255 means the routing information source > cannot be trusted at all and should be ignored. > > When the optional access list number is used with this command, it is > applied when a network is being inserted into the routing table. This > behavior allows filtering of networks according to the IP address of the > router supplying the routing information. This could be used, as an > example, to filter out possibly incorrect routing information from > routers not under your administrative control. > > > Always set the administrative distance from the least to the most > specific network. > > Examples > > In the following example, the router igrp global configuration command > sets up IGRP routing in autonomous system number 109. The network router > configuration commands specify IGRP routing on networks 192.31.7.0 and > 128.88.0.0. The first distance router configuration command sets the > default administrative distance to 255, which instructs the Cisco IOS > software to ignore all routing updates from routers for which an > explicit distance has not been set. The second distance command sets the > administrative distance for all routers on the Class C network > 192.31.7.0 to 90. The third distance command sets the administrative > distance for the router with the address 128.88.1.3 to 120. > > router igrp 109 > network 192.31.7.0 > network 128.88.0.0 > distance 255 > distance 90 192.31.7.0 0.0.0.255 > distance 120 128.88.1.3 0.0.0.0 > > > ----------------------------------------------------------------------------- --- > Note In this example, the distance command specifies an > administrative distance of 255 for networks 192. 31.7.0 and 128.88.0.0. > The second distance command specifies an administrative distance of 90 > for network 192.31.7.0. The third distance command specifies an > administrative distance of 120 for network 128.88.0.0. > > ----------------------------------------------------------------------------- --- > > In the following example, the set distance is from the least to the most > specific network. > > router igrp 100 > network 10.0.0.0 > distance 22 10.0.0.0 > distance 33 10.11.0.0 0.0.255.255 > distance 44 10.11.12.0 0.0.0.255 > > > ----------------------------------------------------------------------------- --- > Note In this example, adding distance 255 to the end of the list > would override the distance values for all networks within the range > specified in the example. The result is that the distance values are set > to 255. > > Tshon > > ying chang wrote: > > > Thanks to you and Bob, I think I understand how it works now. In my > > case, we could not do it, because they are executed in order thus the > > second statement will overwrite the first one. It sure is an > > interesting way to control routes though. > > > > Thanks, > > Chang > > > >> From: "Wade Edwards" <wade.edwards@powerupnetworks.com> > >> Reply-To: "Wade Edwards" <wade.edwards@powerupnetworks.com> > >> To: "ying chang" <ying_c@hotmail.com> > >> CC: <ccielab@groupstudy.com> > >> Subject: RE: Manipulate administrative distance > >> Date: Fri, 1 Mar 2002 14:58:20 -0600 > >> > >> This is an interesting dilemma. The problem is that you can only have > >> one distance statement that has a particular network address and > >> wildcard mask. So this is what I purpose, I don't know if this will > >> work but, do two distance statements one pointing directly to the > >> neighbor address and the other pointing to the subnet where the neighbor > >> is coming from. On one distance statement place an access-list allowing > >> only one set of routes. On the other statement place another > >> access-list allowing only the other set of routes. I don't know if this > >> will work because one might take precedence over the other but it is > >> worth a try. > >> > >> L8r. > >> > >> -----Original Message----- > >> From: ying chang [mailto:ying_c@hotmail.com] > >> Sent: Friday, March 01, 2002 1:57 PM > >> To: Wade Edwards > >> Cc: ccielab@groupstudy.com > >> Subject: RE: Manipulate administrative distance > >> > >> Hopefully I can learn how to use it correctly. The CDROM > >> http://127.0.0.1:8080/cc/td/doc/product/software/ios121/121cgcr/ip_r/ipr > >> prt2/1rdindep.htm#xtocid172612 > >> has a few examples, but I could not make them work for me. > >> > >> Let's get back to my original question, R3 passes 192.168.1.0/24 and > >> 172.160.0.0/16 to R2, how can I change their AD to 192 and 172 > >> respectively? > >> As you can see from the sample output, it does work on 150.100.1.0/24 > >> and > >> 150.100.2.0/24 which was passed from R1 and was changed to 130. Am I > >> missing > >> something here? > >> > >> By the way, please ignore my comment on subnet 172. Doyle I chap 13 has > >> some > >> examples with acl. > >> > >> Below is the output from debug ip igrp tran: > >> > >> r2#debug ip igrp trans > >> IGRP protocol debugging is on > >> r2# > >> 06:51:25: IGRP: received update from 150.100.11.1 on Serial1 > >> 06:51:25: subnet 150.100.50.0, metric 160350 (neighbor 158350) > >> 06:51:25: subnet 150.100.2.0, metric 160350 (neighbor 158350) > >> 06:51:25: subnet 150.100.1.0, metric 10576 (neighbor 8576) > >> 06:51:25: subnet 150.100.10.0, metric 8576 (neighbor 1100) > >> 06:51:25: IGRP: received update from 160.100.77.125 on Ethernet0 > >> 06:51:25: network 172.160.0.0, metric 1600 (neighbor 501) > >> 06:51:25: network 192.168.1.0, metric 1600 (neighbor 501) > >> r2# > >> > >> Thanks, > >> Chang > >> > >> > >> >From: "Wade Edwards" <wade.edwards@powerupnetworks.com> > >> >To: "ying chang" <ying_c@hotmail.com> > >> >CC: <ccielab@groupstudy.com> > >> >Subject: RE: Manupulate administrative distance > >> >Date: Fri, 1 Mar 2002 13:10:05 -0600 > >> > > >> >I think you are not understanding the distance command. The IP address > >> >and wildcard mask is used to change the distance of the routes learned > >> >from the neighbor specified by the IP address and wildcard mask. The > >> IP > >> >address and wildcard mask does not apply to the routes themselves. > >> > > >> >HTH L8r. > >> > > >> > -----Original Message----- > >> >From: ying chang [mailto:ying_c@hotmail.com] > >> >Sent: Friday, March 01, 2002 12:03 PM > >> >To: ccielab@groupstudy.com > >> >Subject: Manupulate administrative distance > >> > > >> >Hi, > >> > > >> >Can someone explain to me why I got 105 instead of 172 and 192 from the > >> >distance command I have in my config? The toplogy is > >> > > >> >OSPF/IGRP redistribution point > >> >(150.100.1.0,150.100.2.0,150.100.50.0)<-150.100.11.0->R2/IGRP<-160.100. > >> 0 > >> >.0-->R3/IGRP(172.16.0.0,192.168.1.0) > >> > > >> >IGRP is the only protocol that is used in R2. Config and output are at > >> >the > >> >bottom of the message. I have comments in my config for what I'm trying > >> >to > >> >do. > >> > > >> >Thanks, > >> >Chang > >> > > >> >router igrp 100 > >> >timers basic 10 30 30 60 > >> >network 150.100.0.0 > >> >network 160.100.0.0 > >> >distance 105 <-- Change default to 105 > >> >distance 130 150.100.0.0 0.0.255.255 sub150 <-- modify 150.100.1.0 and > >> >2.0 > >> >to 130 > >> >distance 192 192.168.1.0 0.0.0.255 sub192 <-- modify 192.168.1.0 to 192 > >> >distance 172 172.160.0.0 0.0.255.255 <-- Doyle's sample does not use > >> >access-list > >> >! > >> >! > >> >ip access-list standard sub150 > >> >permit 150.100.1.0 0.0.0.255 > >> >permit 150.100.2.0 0.0.0.255 > >> >ip access-list standard sub192 > >> >permit 192.168.1.0 0.0.0.255 > >> > > >> >---------------------------------------- > >> >Interfaces: > >> > > >> >r2#siib > >> >Interface IP-Address OK? Method Status > >> > > >> >Prot > >> >ocol > >> >Ethernet0 160.100.77.121 YES NVRAM up > >> > > >> >up > >> > > >> >Ethernet1 unassigned YES NVRAM administratively > >> >down > >> >down > >> > > >> >Serial0 unassigned YES NVRAM administratively > >> >down > >> >down > >> > > >> >Serial1 150.100.11.2 YES NVRAM up > >> > > >> >up > >> >------------------------------------------ > >> >Routing table: > >> > > >> >r2#sir > >> >Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - > >> BGP > >> > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area > >> > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 > >> > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP > >> > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS > >> >inter > >> >area > >> > * - candidate default, U - per-user static route, o - ODR > >> > P - periodic downloaded static route > >> > > >> >Gateway of last resort is not set > >> > > >> >I 172.160.0.0/16 [105/1600] via 160.100.77.125, 00:00:07, Ethernet0 > >> ><--- > >> >??? > >> > 160.100.0.0/24 is subnetted, 1 subnets > >> >C 160.100.77.0 is directly connected, Ethernet0 > >> >I 192.168.1.0/24 [105/1600] via 160.100.77.125, 00:00:07, Ethernet0 > >> ><--- > >> >??? > >> > 150.100.0.0/24 is subnetted, 5 subnets > >> >I 150.100.50.0 [105/160350] via 150.100.11.1, 00:00:04, Serial1 > >> >I 150.100.2.0 [130/160350] via 150.100.11.1, 00:00:04, Serial1 > >> ><--- > >> >Modified > >> >I 150.100.1.0 [130/10576] via 150.100.11.1, 00:00:04, Serial1 > >> ><--- > >> >Modified > >> >I 150.100.10.0 [105/8576] via 150.100.11.1, 00:00:05, Serial1 > >> >C 150.100.11.0 is directly connected, Serial1 > >> > > >> > > >> > > >> > > >> > > >> > > >> > > >> >
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