Ch. 4.6 Flashcards
What should you do if a host cannot perform neighbor discovery to contact other nodes locally?
ipconfig
ip / ifconfig
Check host configuration
Which of these Hosts will have an issue? Why?
Host A: IP: 198.51.100.10
Mask: 255.255.255.240
Host B: IP: 198.51.100.11
Mask: 255.255.255.240
Host C: IP: 198.51.100.21
Mask: 255.255.255.240
C
Subnet mask is incorrect
What happens if Windows detects a duplicate IP address?
Display a warning and disable the IP
What happens if Linux detects a duplicate IP address?
May log a warning
How to resolve issue if 2 hosts have same IP address on Windows?
Obtain the MAC addresses of both interfaces using ping and then arp -a to examine the ARP cache table.
How to resolve issue if 2 hosts have same IP address on Linux?
On Linux, you can use the arping tool (arping -D) to report duplicate replies. Once identified, configure each host to use a unique address
How to resolve issue if 2 hosts have the duplicate MAC address?
Use “arp” to verify MAC addresses on host
ipconfig or ip neigh to check MAC addresses on interface
IP Forwarding checklist
Check for connectivity issues
ping loopback
ping host
ping gateway
ping remote host
ping host name
Establish Session
What does pinging 127.0.0.1 do?
Why would you do it?
How do you troubleshoot if failure?
Pings loopback address
Verify if TCP/IP is installed
Reinstall network protocol stack
What does pinging the IP address of the local host do?
How do you troubleshoot if failure?
Check configuration error
Adapter or driver could be faulty
When should you suspect an incorrect IP address or netmask?
If local host cannot be pinged
Error: Destination is unreachable
When should you suspect a Data Link or Physical layer issue?
If the network configurations are correct
When should you check the default gateway?
If you can’t ping the remote host
What should you be aware when doing ping tests?
ICMP could be blocked by firewall or security software
