how to configured twor routers cisco 1841 Extended ACL with steps as follows ip routing
Here is a simple step-by-step guide to configure two Cisco 1841 Integrated Services Router routers using Extended ACL with IP routing.
Network Example
Topology
PC1 ---- Router1 -------- Router2 ---- PC2
Fa0/0 S0/0 S0/0 Fa0/0
IP Addressing Table
| Device | Interface | IP Address | Subnet Mask |
|---|---|---|---|
| Router1 | Fa0/0 | 192.168.1.1 | 255.255.255.0 |
| Router1 | S0/0 | 10.0.0.1 | 255.255.255.252 |
| Router2 | S0/0 | 10.0.0.2 | 255.255.255.252 |
| Router2 | Fa0/0 | 192.168.2.1 | 255.255.255.0 |
| PC1 | NIC | 192.168.1.10 | 255.255.255.0 |
| PC2 | NIC | 192.168.2.10 | 255.255.255.0 |
Step 1: Connect the Routers
Use:
Console cable for configuration
Serial DCE/DTE cable between routers
Ethernet cable to PCs
Step 2: Configure Router1
Enter Configuration Mode
enable
configure terminal
Configure FastEthernet Interface
interface fastethernet0/0
ip address 192.168.1.1 255.255.255.0
no shutdown
exit
Configure Serial Interface
interface serial0/0/0
ip address 10.0.0.1 255.255.255.252
clock rate 64000
no shutdown
exit
Add Static Route
ip route 192.168.2.0 255.255.255.0 10.0.0.2
Step 3: Configure Router2
enable
configure terminal
Configure FastEthernet
interface fastethernet0/0
ip address 192.168.2.1 255.255.255.0
no shutdown
exit
Configure Serial Interface
interface serial0/0/0
ip address 10.0.0.2 255.255.255.252
no shutdown
exit
Add Static Route
ip route 192.168.1.0 255.255.255.0 10.0.0.1
Step 4: Configure Extended ACL
Example:
Block PC1 from accessing PC2 using ping.
Configure ACL on Router1
access-list 101 deny icmp host 192.168.1.10 host 192.168.2.10
access-list 101 permit ip any any
Step 5: Apply ACL to Interface
Apply ACL inbound on FastEthernet0/0.
interface fastethernet0/0
ip access-group 101 in
exit
Step 6: Save Configuration
On both routers:
copy running-config startup-config
Step 7: Verify Configuration
Check Interfaces
show ip interface brief
Check Routing Table
show ip route
Check ACL
show access-lists
Step 8: Test Connectivity
From PC1:
ping 192.168.2.10
Result:
Ping blocked by Extended ACL
Other traffic allowed
Important Extended ACL Notes
Extended ACL can filter:
Source IP
Destination IP
Protocols
Port numbers
Example syntax:
access-list 101 permit tcp any any eq 80
This allows HTTP traffic only.
Useful Commands
| Command | Purpose |
|---|---|
| show running-config | View configuration |
| show ip route | View routes |
| show access-lists | View ACL rules |
| no access-list 101 | Delete ACL |
Example Complete Router1 Configuration
enable
configure terminal
interface fastethernet0/0
ip address 192.168.1.1 255.255.255.0
no shutdown
interface serial0/0/0
ip address 10.0.0.1 255.255.255.252
clock rate 64000
no shutdown
ip route 192.168.2.0 255.255.255.0 10.0.0.2
access-list 101 deny icmp host 192.168.1.10 host 192.168.2.10
access-list 101 permit ip any any
interface fastethernet0/0
ip access-group 101 in
end
copy running-config startup-config