Building network automation solutions

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Create initial router configurations from dynagen topology

I've always considered building (almost identical) initial router configurations a waste of time, more so when I had to enter them manually, enabling interfaces, configuring IP addresses and Frame Relay subinterfaces on the fly … as well as entering dozens of commands that I feel should be present in every router configuration.

When I finally had enough, I've stopped my non-critical lab tests for a few weeks (that's why there's still no answer on the very good question whether the NBAR started by NAT is of any use) and wrote configMaker: a PERL script that parses dynagen lab topology and produces initial router configurations based on a template file that you can adjust to your own needs. Read more about it in the CT3 wiki.


  1. Nice script but how about the reverse - real configs -> create dynagen topo? any good pointers?

  2. How would you figure out what's connected in real world based on configs only?
  3. ip addresses - links have /30 or /31 on them? Multi router links like vlan trunks or FR serial links ... manual probably.
  4. Unnumbered interfaces?
  5. there are 100s of exceptions I guess
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