This specifies whether the stack will attempt to detect Maximum
Transmission Unit (MTU) routers that do not send back ICMP fragmentation-needed messages. ICMP (Internet Control
Message Protocol) is defined in STD5, RFC 792. With this feature enabled, TCP will try to send segments without
the Don't Fragment bit set if several re-transmissions of a segment go unacknowledged. If the segment is acknowledged
as a result, the MTU will be decreased and the Don't Fragment bit will be set in future packets on the connection.
Enabling black hole detection increases the maximum number of re-transmissions performed for a given segment. Setting
this parameter when it is not needed can cause performance degradation. However, if the router is not sending back
the ICMP messages, then PMTU Discovery will not work. This can cause an even greater loss of performance. PMTU
Black Hole Detect is disabled by default.