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Fetch the Gateway Ip Address

Terminal - Fetch the Gateway Ip Address
netstat -nr | awk 'BEGIN {while ($3!="0.0.0.0") getline; print $2}'
2010-03-07 01:47:55
User: freethinker
Functions: awk netstat
1
Fetch the Gateway Ip Address

This is to fetch the Gateway Ip Address of a machine. Use the below format to put the value in a variable if you wish to find the gateway ip in a script

GATEWAY=$(netstat -nr | awk 'BEGIN {while ($3!="0.0.0.0") getline; print $2}')

Alternatives

There are 6 alternatives - vote for the best!

Terminal - Alternatives
ip route list match 0.0.0.0/0 | cut -d " " -f 3
2010-03-07 15:41:18
User: BaS
Functions: cut route
2

Better use iproute2 !

/sbin/route -n | grep "^0\.0\.0\.0" | awk '{ print $2 }'
2010-03-07 13:59:57
User: BorneBjoern
Functions: awk grep
0

same thing without loop ;)

Know a better way?

If you can do better, submit your command here.

What others think

Well unfortunately this did not work on my BSD box... but you could us this instead.

For FreeBSD either of these will work.

awk -F '"' '/defaultrouter/{print $2}' /etc/rc.conf

netstat -nr | awk '/default/{ print $2}'

Now on Mac OS X it get's a little trickier because IPv6 is enabled by default. The following works for me.

netstat -nr | awk '/default/{ print $2;exit}'

Oh on FreeBSD there's a third option if your are running bash but it can get messy. This reads the file into the shell as an include script Remember bash is not installed by default on and BSD.

. /etc/rc.conf

echo $defaultrouter

Cheers,

Mikel King

Comment by mikelking 281 weeks and 4 days ago

Pretty cool, I should have actually used the subject line "Fetch the Gateway Ip Address on Linux" ...

Comment by freethinker 281 weeks and 4 days ago

Your point of view

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