Category: Routing
Configuration Example, Routing
Cisco DHCP server & VRF
I had some issues while configuring some VRF’s on a Cisco router and using that router as a DHCP server. First of all the router wasn’t binding any DHCP request. The DHCP server configuration is defined below. ip dhcp pool guest vrf vrf-guest network 10.10.0.0 255.255.252.0 default-router 10.10.0.1 domain-name internet-only.nl dns-server 208.67.222.222 208.67.220.222 The configuration … Read More
Configuration Example, Firewalling, Routing
NBAR and smart filtering
NBAR (Network Based Application Recognition) is a cool Cisco tool to identify and classify content flowing through a router. You can identify applications as mission critical, business-related, non-critical or unwanted. Once these mission critical applications are classified they can be guaranteed a minimum amount of bandwidth, policy routed, and marked for preferential treatment. Non-critical applications … Read More
XS4ALL, Cisco 877 and IPv6
A while ago my ISP XS4ALL started with the distribution of IPv6 prefixes to their customers. So as a network engineer I wanted to have my own /48 prefix. Sadly I didn’t had time to start testing at the beginning of the IPv6 “launch”. Last week I found some time to start my testing. I … Read More
Configuration Example, Routing
Policy-based routing in a nutshell
Lately I received some questions about routing decisions and how to influence the routing decisions via access control lists. The following example shows a simple configuration for policy-based routing. The example uses the following logical setup: I configured two routers and connected each router to two PVC’s on the same ATM interface. I configured one … Read More
ISDN Backup – still alive?
Nowadays everybody wants redundancy within their network, especially when using remote sites. Customers are using multiple ISP’s for redundancy and/or configure BGP solutions. In the old days (hear me talking with my 27 years) ISDN was often used for backup purposes and I still use it sometimes as redundancy mechanism. Everybody knows that bandwidth is … Read More
Huh? Interface SSLVPN-VIF0?
While checking interface statistics on a Cisco 3845, I noticed the following layer 3 interfaces. Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0 74.124.155.67 YES NVRAM up up GigabitEthernet0/1 10.10.10.1 YES NVRAM up up GigabitEthernet0/0/0 unassigned YES NVRAM administratively down down SSLVPN-VIF0 unassigned NO unset up up Tunnel0 192.168.255.2 YES NVRAM up up I can explain … Read More