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This program is designed to assist network administrators in configuring firewall rules (ACLs – Access Control Lists) on Cisco routers efficiently and with customization. It covers everything from basic setups to advanced features like logging, geolocation, and time-based rules.
You Should Know:
Basic Cisco ACL Configuration
Access Control Lists (ACLs) filter traffic based on rules applied to router interfaces. Here’s how to create a standard ACL:
Router(config)# access-list 10 permit 192.168.1.0 0.0.0.255 Router(config)# access-list 10 deny any Router(config)# interface GigabitEthernet0/0 Router(config-if)# ip access-group 10 in
Extended ACLs for Advanced Filtering
Extended ACLs provide granular control over traffic:
Router(config)# access-list 101 permit tcp 192.168.1.0 0.0.0.255 any eq 80 Router(config)# access-list 101 deny ip any any Router(config)# interface GigabitEthernet0/1 Router(config-if)# ip access-group 101 out
Time-Based ACLs
Restrict access during specific time periods:
Router(config)# time-range WORK-HOURS Router(config-time-range)# periodic weekdays 9:00 to 17:00 Router(config)# access-list 102 permit tcp any any eq 22 time-range WORK-HOURS
Logging ACL Hits
Monitor ACL activity with logging:
Router(config)# access-list 103 permit tcp any any eq 22 log
Geolocation-Based ACL (Using Object Groups)
Block traffic from specific countries:
Router(config)# object-group network COUNTRY-BLOCK Router(config-network-group)# 41.0.0.0/8 Router(config)# access-list 104 deny ip object-group COUNTRY-BLOCK any
Verifying ACLs
Check applied ACLs and hits:
Router# show access-lists Router# show ip interface GigabitEthernet0/0
What Undercode Say:
ACLs are fundamental in network security, ensuring only authorized traffic flows through. Automation tools like the Interactive ACL Generator simplify complex setups, but understanding manual configurations remains crucial. For deeper security, combine ACLs with:
- Firewall rules (
iptablesin Linux) - Intrusion Detection Systems (Snort, Suricata)
- Network segmentation (VLANs, Private Subnets)
Linux Alternative (`iptables` Example):
iptables -A INPUT -p tcp --dport 22 -s 192.168.1.0/24 -j ACCEPT iptables -A INPUT -p tcp --dport 22 -j DROP
Windows Command (`netsh` Example):
netsh advfirewall firewall add rule name="Block SSH" dir=in action=block protocol=TCP localport=22
Expected Output:
A structured ACL deployment log, such as:
Extended IP access list 101 10 permit tcp 192.168.1.0 0.0.0.255 any eq www (5 matches) 20 deny ip any any (10 matches)
For further reading:
References:
Reported By: Fabiano Meda – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
