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OSPF with enabled MD5 authentication is not establishing adjacency due to MTU mismatch
Symptoms
  • OSPF with enabled MD5 authentication is not establishing adjacency.
Cause

When MD5 authentication is enabled, OSPF subtracts 16 bytes from the MTU it advertises. This is causing the OSPF neighbor (e.g., Cisco router) not to establish adjacency.


Solution
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