Appendix A Network Troubleshooting
P-870HN-51D User’s Guide
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In this example, we abridge the tracert results table to show only server IP
addresses and not domain names by using the -d parameter. We also use the -h
parameter to limit the number of hops to 5 to test local connections only.
arp
Local network transmission is based on MAC addresses. Data transmission
between two networks is based on IP addresses.
Address Resolution Protocol (ARP) is a protocol that converts IP addresses into
MAC addresses. Before a computer transmits data to an IP address on the same
network, it will check whether the IP address exists in its ARP table. If it does, the
computer then sends the data directly to the mapped MAC address. If it does not,
the computer broadcasts an ARP request to the network. The host whose MAC
address maps to the IP address responds.
When you use ping to check the connection to a computer, no response does not
mean the computer is not alive on the network. The destination computer may be
configured not to respond to any ping requests. However, you can use the arp -a
command line utility to check the IP addresses and MAC addresses of your
neighboring computers or devices.
Syntax: arp -a
Parameters: arp [-d inet_addr] [-s inet_addr eth_addr]
The -d parameter can be use alone to remove all entries from an arp table or in
conjunction with an IP address to remove just that IP address (inet_addr). The -
s parameter allows you to add entries based on IP address (inet_addr) and/or
MAC address (eth_addr).
There are other parameters but these are the only ones you need to use for now.
C:\>tracert -d -h 5 www.zyxel.com
Tracing route to a1524.g.akamai.net [203.69.113.16]
over a maximum of 5 hops:
1 <1 ms <1 ms <1 ms 172.23.31.254
2 5 ms 4 ms 4 ms 172.23.6.113
3 5 ms 5 ms 6 ms 172.23.6.253
4 17 ms 16 ms 14 ms 218.160.188.254
5 24 ms 25 ms 24 ms 10.42.232.150
Trace complete.
C:\>
