- [Instructor] In Windows,
one of the first network troubleshooting tools
you will use is IP config.
It allows you to quickly verify IP information configured
on network interfaces.
I start by opening a command prompt.
I can select start and type CMD
and then hit enter. Typing IP config
with no additional parameters shows me all
of the network interfaces on my computer,
along with IPV six addresses, IPV
four addresses, sub-net mask and default gateway.
Any interfaces that are unplugged show
up as media disconnected.
I'm going to go ahead and clear the screen.
There is quite a bit more information that can be shown
by typing IP config/all.
This shows the same output as the previous command
but also gives the physical address or Mac address
for each interface, whether DHCP is enabled or not,
when the DHCP and lease was obtained,
and when it will expire. /all also
lists the IP address
of the DHCP and or manually configured DNS servers.
If DHCP is enabled on my network
there are additional control commands I can use
with IP config.
If there's an IP address assigned via DHCP to an interface
IP config/release will remove it.
By default, if I enter the command
without specifying a specific interface
it will release the DHCP leases assigned to all interfaces.
I can use wildcards in the interface name to make it easier.
These are simply asterix. On this machine
I've got wireless land adaptor wifi, so I'll type
IPconfig/release*FI.
Once the IPS have been released, I can query
for new ones by issuing IPconfig/renew.
In this case, I'm just going to hit the
up arrow and change my command to renew.
Again, I can choose to specify an interface or not.
For you IPV six lovers out there,
IPconfig/release6 and IPconfig/renew6 will control
V6 DCP IP addresses.
There are also a few DNS commands
that are great troubleshooting tools.
I can flush the local DNS cache
with IPconfig/flushDNS.
Alternately if I want to view the DNS cache
I can issue IPconfig/displayDNS.
Display DNS shows each entry, the type of record
that it is, be it a record or C name, it's TTL,
and ultimately what it resolved to.
An A record will be a direct DNS
to IP mapping, where a C name is a DNS entry that points
to another DNS entry for ultimate resolution.
Linux isn't wholly different.
To list the IP addresses present on the server
I simply type IP ADDR.
To view the routing table information
like the default gateway
the IP route command can be entered.
These simple commands are used daily
in the world of network support and administration.