ISIS backdoor

R1#show is da

IS-IS Level-1 Link State Database:

LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime      ATT/P/OL

R1.00-00            * 0x00000006   0x4C93          701                          0/0/0

R2.00-00              0x00000009   0xBAED        1186                        1/0/0

R2.01-00              0x00000002   0x9B0F        699                           0/0/0

Cau hinh sao cho R1 khong co default route tren bang dinh tuyen. Bang 2 cach. Cau hinh tren R1 or tren R2

• Cau hinh R1:

router isis  net 49.0012.0000.1111.0000.00  is-type level-1  ignore-attached-bit

Command tren bi an trong IOS.

R1# show ip route      1.0.0.0/24 is subnetted, 1 subnets C       1.1.1.0 is directly connected, Loopback0      2.0.0.0/24 is subnetted, 1 subnets i L1    2.2.2.0 [115/20] via 10.1.12.2, FastEthernet0/0      10.0.0.0/24 is subnetted, 1 subnets C       10.1.12.0 is directly connected, FastEthernet0/0 R1#show isis da IS-IS Level-1 Link State Database: LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime      ATT/P/OL R1.00-00            * 0x00000006   0x4C93        520               0/0/0 R2.00-00              0x00000009   0xBAED        1006              1/0/0 R2.01-00              0x00000002   0x9B0F        518               0/0/0

=> R1 van nhan ATT = 1. tuy nhien tren bang dinh tuyen khong co default-route.

• Cau hinh R2.

router isis  net 49.0012.0000.2222.0000.00  is-type level-1-2 backdoor

R1#show isis da IS-IS Level-1 Link State Database: LSPID                 LSP Seq Num  LSP Checksum  LSP Holdtime      ATT/P/OL R1.00-00            * 0x00000007   0x4A94        1149              0/0/0 R2.00-00              0x0000000A   0xB0FE        1132               0/0/0 R2.01-00              0x00000003   0x9910        1020               0/0/0

=> R1 set gia tri ATT = 0.  khong nhan defaul-route.

• Nhan xet:
• Cach 1: muon filter default-route tren tung router
• Cach 2: filtter default-route trong 1 area level 1

• Tuy theo yeu cau, su dung cach phu hop :)