Redistribution notes

Through all the reading and practice labs, these are some redistribution notes that I thought were very useful and helped me allot. So I'm sharing and maybe it'll help someone understand or see things differently.

Redistribution

• When redistributing from OSPF in to BGP, by default, BGP only accepts internal routes not external type-1 or type-2.
• When redistributing into OSPF all redistributed routes get a metric of 20, except BGP gets a metric of 1.
• EIGRP needs a default-metric command or a metric when redistributing with route-map or with the redistribute metric xxx command.
• Watch for RIP metrics set to redistributed routes, might end up with 16, use metric, again in route-map or redistribute metric command.
• Watch for administrative distance problems, especially since EIGRP has lower distance than OSPF.
• Beware of the metric used by RIP
• Redistributing in to RIP requires a metric or default-metric or it may get set to 16.
• Always filter routes when doing redistribution the use of route TAGS is extremely useful and sometimes necessary (to conserve time and headaches).
• BGP only redistributes eBGP routes by default (bgp redistribute internal) to change that.
• Make note of routes in routing table and from which protocol. Only routes in routing table get redistributed.
• Always watch for multiple points of redistribution and routes from a higher AD protocol going into a lower AD protocol then back into Higher AD, use route TAGS as well for this.
• Only change Protocol AD if absolutely necessary.
• route-maps are extremely useful in redistribution as in BGP.

If you have further notes that are useful and wish to share, well then go ahead an leave me your thoughts. I'm working on a screencast of my own pitfalls and practice. Will post it up as soon as I can.