Inserting routes into BGP - aggregates and Null0

• Remember! Matching route must exist in routing table to be announced via BGP

• router bgp 1

  • network 198.10.0.0 mask 255.255.0.0

• ip route 198.10.0.0 255.255.0.0 null0 250

• Static route to “null0” often used for aggregation

  • packets sent here if there is no more specific match in routing table
  • distance of 250 ensures last resort

• Often used to nail up routes for stability

  • can’t flap!! :)

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