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Cisco Router

Table of contents

  1. Basic setup
  2. Administrative Distance
  3. Static Route
  4. OSPF (Open Shortest Path First)
  5. NAT
  6. ACL

Basic setup 

show ip route summary

Administrative Distance 

Routing Protocol                    Administrative Distance
Directly connected interface        0
Static route                        1
OSPF                                110
RIP                                 120

Static Route 

ip route 172.16.0.0 255.255.0.0 e0/0 192.168.12.2
ip route 0.0.0.0 0.0.0.0 e0/0 192.168.12.2
ip route 0.0.0.0 0.0.0.0 e0/1 192.168.13.3 10

OSPF (Open Shortest Path First) 

router ospf 1 // router ospf process-id
interface fastEthernet 0/1
ip ospf 1 area 0
ip ospf cost 1
interface fastEthernet 0/2
ip ospf 1 area 0
ip ospf cost 2
interface vlan 10
ip ospf 1 area 1
router ospf 1
passive-interface vlan 10
show ip ospf interface brief
show ip ospf neighbor
show ip route ospf
reference-bandwidth (100 Mbps by default)
router ospf 1
auto-cost reference-bandwidth 1000 (The reference bandwidth in terms of Mbits per second)
interface fastEthernet 0/1
bandwidth 100000 (Bandwidth in kilobits)
Cost = reference-bandwidth / bandwidth

NAT 

interface Ethernet0
ip address 192.168.1.1 255.255.255.0
ip nat inside
interface Ethernet1
ip address 211.120.200.2 255.255.255.0
ip nat outside
ip nat inside static 192.168.1.100 211.120.200.100
show ip nat translations

ACL 

# FTP (Active Mode)
access-list 102 permit tcp any host 192.168.1.100 eq ftp
access-list 102 permit tcp any host 192.168.1.100 eq ftp-data established
# FTP (Passive Mode)
access-list 102 permit tcp any host 192.168.1.100 eq ftp
access-list 102 permit tcp any host 192.168.1.100 gt 1024
# SMTP
access-list 102 permit tcp any host 192.168.1.100 eq smtp
# https://www.cisco.com/c/zh_cn/support/docs/ip/access-lists/26448-ACLsamples.html