R4#
R4#sh ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, 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, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is 192.168.1.3 to network 0.0.0.0

i*L1  0.0.0.0/0 [115/20] via 192.168.1.3, 00:18:28, FastEthernet0/0
      10.0.0.0/24 is subnetted, 1 subnets
i L1     10.0.0.0 [115/30] via 192.168.1.3, 00:18:28, FastEthernet0/0
i L1  192.168.0.0/24 [115/20] via 192.168.1.3, 00:18:28, FastEthernet0/0
      192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.1.0/24 is directly connected, FastEthernet0/0
L        192.168.1.4/32 is directly connected, FastEthernet0/0
i L1  192.168.2.0/24 [115/30] via 192.168.1.3, 00:18:28, FastEthernet0/0
R4#
R4#sh isis topology

IS-IS TID 0 paths to level-1 routers
System Id            Metric     Next-Hop             Interface   SNPA
R2                   20         R3                   Fa0/0       ca02.0486.0006
R3                   10         R3                   Fa0/0       ca02.0486.0006
R4                   --
R5                   30         R3                   Fa0/0       ca02.0486.0006
R4#
R4#sh isis neighbors

System Id      Type Interface   IP Address      State Holdtime Circuit Id
R3             L1   Fa0/0       192.168.1.3     UP    22       R4.01
R4#