Cisco Router Interfaces - Routing and NAT

Cisco Router Interfaces - Routing and NAT

Configure two interfaces

1. Perform these commands to configure FastEthernet0 interface (outside):

   enable
   configure terminal
   interface FastEthernet0
   ip address 172.17.120.21 255.255.255.0
   no shutdown
   exit 
   exit
   show ip interface FastEthernet0

2. Perform these commands to configure FastEthernet1 interface (inside):

   enable
   configure terminal
   interface FastEthernet1
   ip address 10.0.0.1 255.255.0.0
   no shutdown
   exit 
   exit
   show ip interface FastEthernet1

3. Connect the FastEthernet1 port with a computer or similar device and check that pings work:

   On router:
   ==========
   ping 10.0.8.10
   On another device:
   ==================
   ping 10.0.0.1

4. Set up gateway and DNS:

   config t
   ip routing
   ip route 0.0.0.0 0.0.0.0 FastEthernet0
   ip name-server 195.122.1.59

5. Try pinging some external DNS name from router's terminal console.

Configure NAT

1. NAT can be configured by these commands (unused):

   conf t
   interface FastEthernet0
   ip nat outside
   ^Z
   show ip interface FastEthernet0
   conf t
   interface FastEthernet1
   ip nat inside
   ^Z

2. Some other (unused) commands:

   conf t
   ip nat pool ovrld 172.17.120.23 172.17.120.23 prefix 24
   ip nat inside source list 7 pool ovrld overload
   access-list 7 permit 10.0.0.160 0.0.0.31
   access-list 7 permit 10.0.1.100
   ^Z
   show ip nat translations

3. Examples with static translations (unused):

   configure terminal
   ip nat inside source static 10.0.0.160 172.17.120.23
   ip nat inside source static 10.0.0.161 172.17.120.23

Links

1. http://www.cisco.com/en/US/products/sw/iosswrel/ps5187/products_tech_note09186a00802017a1.shtml - Reset a Cisco Router to Factory Defaults.
2. http://routersimulator.certexams.com/network-simulator-labs/configuring-ethernet-interfaces-on-a-router-network.html
3. http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a00800c525f.shtml
4. http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094e77.shtml
5. http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094e77.shtml#topic3
6. http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094837.shtml
7. http://www.ietf.org/rfc/rfc1631.txt

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