Basically the same as the Strict verifier, but does not try to actually verify a connection if the server is the localhost and the port is a nonstandard port number. Those two conditions will typically mean the connection is being tunnelled through a forwarded port, so the known-hosts file will not be helpful (in general).
Tries to determine if the connection is being tunnelled, and if so, returns true. Otherwise, performs the standard strict verification.
# File lib/net/ssh/verifiers/lenient.rb, line 13 def verify(arguments) return true if tunnelled?(arguments) super end