Diagnosis References - Network Layer

Colasoft Capsa offers expert diagnosis results for the following network layer events

Event Description Severity Possible causes and solutions
Illegal IP Checksum
  • Error in the checksum of IP header.
  • The checksum value is calculated by the sender and written to the packet, and then recalculated from the received packet by the receiver. It indicates an error if the two values are different.
 Fault There is a faulty device in the network.
IP TTL Too Low An IP packet with a time-to-live field set to 1 indicates that the packet is about to expire. Fault
  • An IP packet with a time-to-live field set to 1 indicates that the packet is about to expire. 
  • Network loop. 3. Try to locate the source of the original packet.
IP Address Conflict
  • Typical IP address conflict.
  • Sending free ARP packets to announce the corresponding information to IP addresses and MAC addresses.
  • A host detected another device is trying to use its IP address, conflict occurred and notify the device by ARP.
 Security A device try to use a IP address been used.
ICMP Destination Unreachable Workstation receives an ICMP destination unreachable message Fault The target network or host does not exist.
ICMP Net Unreachable Workstation receives an ICMP network unreachable message. Fault The target network does not exist.
ICMP Host Unreachable Workstation receives an ICMP host unreachable message. Fault The target host does not exist.
ICMP Port Unreachable Workstation receives an ICMP port unreachable message. Fault The target port sent by the workstation is not active on the target host.
ICMP Host Redirect Workstation receives an ICMP redirect message with the Code value set to 1 (redirected data send to host). Performance Router inform the workstation that there's a better route to destination.
ICMP Network Redirect Workstation receives an ICMP redirect message with the Code value set to 0 (redirected data send to network). Performance Router inform the workstation that there's a better route to destination.
ICMP Source Quench Workstation receives an ICMP source restrain message. Fault The workstation that sent the message may be down or reboot.

 

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