FH_InvalidLength - check Fragment Reassembly (Invalid Length)
Host and Router
FH_InvalidLength.seq [-tooloption ...] -pkt FH_InvalidLength.def -tooloption : v6eval tool option
1. Ping to Target (create Neighbor Cache Entries, if not exist) 2. Override Neighbor Cache Entries
Tester Target | | |-------------------------->| | Echo Request (1st) | | | | | |-------------------------->| | Echo Request (2nd) | | | | | |<--------------------------| | ICMP Error | | | | | v v
1. Send Echo Request (1st fragment) 2. Send Echo Request (2nd fragment) 3. Receive ICMP Error
Echo Request (1st fragment) is:
IPv6 Header Version = 6 Traffic Class = 0 FlowLabel = 0 PayloadLength = 527 (not multiple of 8 octets) NextHeader = 56 (Fragment Header) SourceAddress = Tester Link Local Address DestinationAddress = Target Link Local Address
Fragment Header NextHeader = 58 (ICMP) FragmentOffset = 0 (1st fragment) MFlag = 1 (more fragment)
PASS: ICMP Error Received
IPv6 Header Version = 6 Traffic Class = 0 FlowLabel = 0 PayloadLength = 575 NextHeader = 58 (ICMP) SourceAddress = Target Link Local Address Destination Address = Tester Link Local Address
ICMP Error Type = 4 (Parameter Problem) Code = 0 (erroneous header field encounted) Checksum = (auto) Pointer = 4 (Pointer to Payload Length in IPv6 Header) PayloadData = (1st Fragment of Echo Request)
perldoc V6evalTool