Previously in part 1 we discussed route-filtering using the “filter-list” command in OSPF. That was limited to our ABR and ASBRs. With distribute-lists we are able to filter OSPF routes from making to the routing information base/routing table (RIB). If you recall our topology from part 1, well I’ve just added R4 to that. If …
Category Archives: Cisco
Filtering OSPF Routes Part 1
Filtering routes is a little more complicated when we are talking about OSPF. In EIGRP it was simple. Since EIGRP is an advanced distance vector routing protocol, each router doesn’t have a perfect picture of the routing domain, it just has an idea of what’s behind our neighbor. OSPF is of course different. Each OSPF area …
EIGRP Questions to Prepare you for the CCNP!
In my CCNP notes I usually have some questions about each topic to help me solidify the material (along with labs). Here are some EIGRP questions I would recommend trying to answer. If I were you, I would memorize these questions/answers. I promise they will help! Questions: What is the administrative distance of internal EIGRP? …
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Basic EIGRP Manual Summarization and Null0
EIGRP Summarization is used to simplify our routing table and advertise a summary instead of a bunch of prefixes that look the same. My current network topology is simple, I’ve basically configured EIGRP, then used the “network 0.0.0.0” command to advertise everything and form neighbors. Here is what my routing table looks like …
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Basic EIGRP Auto-Summary
In the above topology I have auto-summary enabled on R1 and R2. R3 does not have auto-summary. The result of this config is R1 and R2 will actually advertise the 10.0.0.0/8 network, since both of those 10. networks reside in that classful boundary. Since their only neighbor is R3, R3 will have a duplicate route …
Basic Prevention of Rouge DHCP Servers with DHCP Snooping
What problem are we trying to solve? We want to prevent the rouge DHCP Server from assinging addresses out to our clients. Normally this would be your favorite wanna-be IT employee that brings his own Linksys router in the mix to fix the network 🙂 Of course it can also protect from malicious …
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