Category Archives: CISCO

BGP Aggregate experiment

The BGP aggregate-address can be used to summarise a set of networks into a single prefix. For this post, I just wanted to show the difference between aggregate-address and aggregate-address with summary only. We have below topology. I’m going to summarise prefixes in R1. R1 config hostname R1 ! interface GigabitEthernet0/0 ip address… Read More »

Cisco DHCP Server: Excluding IP Addresses

Most of the time in a small network, we will be using the Layer 3 device as a default gateway and a DHCP server. And most of the time also, we will be excluding the gateway’s ip address from the dhcp pool. Just to save 1 more configuration line and for the sake of knowledge,… Read More »

Microsoft VPN PPTP client through Cisco ASA Firewall

Scenario: Using Microsoft Windows built in VPN Client to connect to remote PPTP VPN server through Cisco ASA firewall. Symptom: Error 619 Solution: In ASA Firewall, enter below command. ASA-active#conf t ASA-active(config)#policy-map global_policy ASA-active(config-pmap)# class inspection_default ASA-active(config-pmap-c)#inspect pptp ASA-active(config-pmap-c)#exit ASA-active(config)#access-list $Inbound_Interface_ACL permit gre $source_ip/network any ASA-active(config)#access-list $Inbound_Interface_ACL permit permit tcp $source_ip/network any eq pptp Common… Read More »

Cisco NAT with route-maps for multiple destinations

object-group network og-rfc1918 /8 /12 /16 ! ip access-list extended acl-nat permit ip object-group og-rfc1918 any ! route-map rm-site-a match ip address acl-nat match interface FastEthernet0/0 ! route-map rm-site-b match ip address acl-nat match interface FastEthernet1/0 ! ip nat inside source route-map rm-site-a interface FastEthernet0/0 overload ip nat inside source route-map rm-site-b… Read More »

Cisco Multi Homed Internet Config

Found this article from Cisco Forum. Credits to original author. Introduction Network Address Translation is a very common feature used to address some issues and also to meet some networks’ requirements such as, overlapped networks and Internet links. In this small document we will discuss a business requirement example, and the main idea behind this… Read More »