From: Omer Ansari (omer@xxxxxxxxxx)
Date: Thu Jul 25 2002 - 07:56:02 GMT-3
Umit,
this is quite interesting... up until now I thought you could never put
the same network on multiple interfaces on a router but it certainly is
possible (tested it )
> interface Serial1/0.1 multipoint
> ip address 1.1.1.1 255.255.255.0
> !
> nterface Serial1/0.3 multipoint
> ip address 1.1.1.2 255.255.255.0
i note that these are multipoint does that add some significance?
can you or anyone explain why this is allowed?
Omer
On Thu, 25 Jul 2002, [iso-8859-1] \mit Askan (TK-Network Gvz|mleri) wrote:
> Hi,
>
> yes you can. the way is a little tricky. look my topology. R2 is hub and
> R3 and R4( authenticated) spokes.
> you must write ip ospf auth under interface, But you have only one int.
> Make 2 multipoint subints and give them ip's at the same block.
> at the situation you can make auth at one subint.
> when you make 2 subints with the same ip block, hub router sees that
> block with 2 different int and one packet goes on true int one packet
> goes on wrong int.
> for solving that problem write static routes or make the ospf net type
> point-to-multipont ( inserts host routes ) for saying go along that way.
>
> I tried it for you : look the configs, it is working
>
> R2........................................
>
> interface Loopback0
> ip address 10.10.10.1 255.255.255.0
> ip ospf network point-to-point
> !
> interface Serial1/0
> no ip address
> encapsulation frame-relay
> no fair-queue
> !
> ip ospf authentication
> ip ospf authentication-key cisco
> ip ospf network point-to-multipoint
> frame-relay map ip 1.1.1.4 204 broadcast
> !
> router ospf 1
> log-adjacency-changes
> network 1.0.0.0 0.255.255.255 area 0
> network 10.0.0.0 0.255.255.255 area 0
>
> R4..........................................................
>
> interface Serial0/0
> ip address 1.1.1.4 255.255.255.0
> encapsulation frame-relay
> ip ospf authentication
> ip ospf authentication-key cisco
> ip ospf network point-to-multipoint
> no arp frame-relay
> frame-relay map ip 1.1.1.1 402 broadcast
> frame-relay map ip 1.1.1.2 402 broadcast
> frame-relay map ip 1.1.1.3 402 broadcast
> no frame-relay inverse-arp
> !
> router ospf 1
> log-adjacency-changes
> network 1.0.0.0 0.255.255.255 area 0
>
> R3....................................................
>
> interface Serial0/0
> ip address 1.1.1.3 255.255.255.0
> encapsulation frame-relay
> ip ospf network point-to-multipoint
> ip ospf priority 0
> no fair-queue
> no arp frame-relay
> frame-relay map ip 1.1.1.1 302 broadcast
> frame-relay map ip 1.1.1.2 302 broadcast
> frame-relay map ip 1.1.1.4 302 broadcast
> no frame-relay inverse-arp
> !
> router ospf 1
> log-adjacency-changes
> network 1.0.0.0 0.255.255.255 area 0
>
> ........................................................................
> ........................................................
>
> R4#sh ip rou
> 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
>
> 1.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
> O 1.1.1.1/32 [110/781] via 1.1.1.2, 00:16:15, Serial0/0
> C 1.1.1.0/24 is directly connected, Serial0/0
> O 1.1.1.3/32 [110/829] via 1.1.1.2, 00:16:15, Serial0/0
> O 1.1.1.2/32 [110/781] via 1.1.1.2, 00:16:15, Serial0/0
> 10.0.0.0/24 is subnetted, 1 subnets
> O 10.10.10.0 [110/782] via 1.1.1.2, 00:16:15, Serial0/0
>
> ........................................................................
> .........................................................
>
> R2
> Serial1/0.3 is up, line protocol is up
> Internet Address 1.1.1.2/24, Area 0
> Process ID 1, Router ID 1.1.1.2, Network Type POINT_TO_MULTIPOINT,
> Cost: 48
> Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,
> Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
> Hello due in 00:00:09
> Index 2/2, flood queue length 0
> Next 0x0(0)/0x0(0)
> Last flood scan length is 1, maximum is 1
> Last flood scan time is 0 msec, maximum is 0 msec
> Neighbor Count is 1, Adjacent neighbor count is 1
> Adjacent with neighbor 1.1.1.4
> Suppress hello for 0 neighbor(s)
> Simple password authentication enabled
> ............................................. OKI DOKI
> .................................
> Serial1/0.1 is up, line protocol is up
> Internet Address 1.1.1.1/24, Area 0
> Process ID 1, Router ID 1.1.1.2, Network Type POINT_TO_MULTIPOINT,
> Cost: 48
> Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,
> Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
> Hello due in 00:00:22
> Index 1/1, flood queue length 0
> Next 0x0(0)/0x0(0)
> Last flood scan length is 1, maximum is 1
> Last flood scan time is 0 msec, maximum is 0 msec
> Neighbor Count is 1, Adjacent neighbor count is 1
> Adjacent with neighbor 1.1.1.3
> Suppress hello for 0 neighbor(s)
>
> Hope this helps
> best Regards
> umit
>
> -----Original Message-----
> From: yakout esmat [mailto:yesmat@iprimus.com.au]
> Sent: Thursday, July 25, 2002 14:09
> To: Groupstudy
> Subject: OSPF interface authentication (not area authent.)
>
>
> I have come across a OSPF Interface authentication issue might or might
> not
> be of significance.
>
> If we have hub and two spokes in frame relay network sharing the same
> subnet.
>
> If I do interface authentication between the hub and one of the spokes
> only,
> I lose adjancey with the other spoke understandably.
>
> Is there a way with which we can do interface ONLY authentication (not
> are
> authentication) between hub and only one of the spokes without loosing
> the
> other spoke??
>
> I would think not, but if any body has insight on this issue, would be
> appreciated.
>
> Cheers
>
> Yakout
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