This week, Terry Slattery and Josh O’Brien talk network configuration management and experiences. Ethan is taking a break from the microphone.
Terry Slattery was the first or the second CCIE depending on how you look at it, and the founder of Netcordia, a network management product for Automated Network Change and Configuration Management tool. We are looking at his Top 5 common network configuration errors, the problems and they cause and what you can do about them with Network Management tools.
Terry’s Top 5 network problems.
- Layer 1 — Duplex mismatch.
- Overlarge VLANs and STP domains, increasing potential for forwarding loops — more common than you would think.
- root bridge not defined or unstable root bridge
- many routers with static default routes defined (and in general, heavy use of static routes is not good. Terry’s advice — use the dynamic protocols to distribute default. Inject statics at the border where connections exist to partners
- lack of route summarization (related to a good IP addressing plan) Terry points out that route summarisation increases routing stability by limiting address range to a geography. Try to limit the number of summarized ranges.
- first hop redundancy protocol with only one router defined which is redundancy failure waiting to happen
- poor configuration change control processes — discussion ranging from configs not matching corporate policies to lack of a change control system and config archive
Terry’s Perl script for summarising Syslog entires to get useful data.
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