linux下如何获取当前能连上网的那个ip地址
linux下怎么获取当前能连上网的那个ip地址
就是在多网卡的情况下，多ip的情况下，怎么判断是哪个网卡ip连接着外网啦
------解决思路----------------------
把其他网卡关了，剩一个，哪个能ping通外网，那个就是外网的ip
------解决思路----------------------
要是route没配好,ping死都出不去....
------解决思路----------------------
http://hawknotes.blogspot.com/2010/06/finding-your-external-ip-address.html
# Determine the public IP address for your DHCP system by bootstrapping
# calls to your gateway/router
# Requires "route," available in Ubuntu package net-tools, and
# nslookup, available in Ubuntu package dnstools
# Disclaimers:
# 1) This works with Verizon FIOS using the Actiontec MI424WR Router
# If you have another system YMMV.
#
# 2) And, as you'll no doubt note, this is set up for a Debian system,
# specifically Ubuntu 10.04 . Package names and installation
# procedures for other systems WILL vary.
#
###
# Start Here:
###
#
# Get Router internal Gateway IP
# Information found on
# http://www.cyberciti.biz/faq/how-to-find-gateway-ip-address/
# If route is not installed, run
# sudo apt-get install net-tools
# and make sure /sbin is in your $PATH
# Note "U" = up, and "G" = gateway
internalip=`route -n
------解决思路----------------------
grep UG
------解决思路----------------------
awk '{print $2}'`
echo Your Gateway\'s Internal IP Address is: $internalip
# Now we need to get the name of the router. If you don't
# have nslookup installed, run
# sudo apt-get install dnsutils
echo -n "Your Gateways's name is: "
routername=`nslookup $internalip
------解决思路----------------------
grep "name ="
------解决思路----------------------
awk '{print $4}'`
# On the Actiontec, at least, the name has an annoying "." at the end.
# Remove it:
routername=${routername%\.}
echo $routername
echo -n "Your Public IP Address is: "
nslookup $routername
------解决思路----------------------
grep Address
------解决思路----------------------
tail -1
------解决思路----------------------
awk '{print $2}'
------解决思路----------------------
这个问题有点复杂。
首先，如果只有一个链路可以通到外网的话，那么要看路由表的设置。如果路由表设置不正确，就连不上外网。一般的，就看default路由了，如果这个路由跟某个网卡上面的IP同一个网段，那么这个IP就是通向外网的那个IP了。
还有一种可能，就是有多个链路可以通到外网。其实我们每个PC，从某种角度来说，都是一个路由器，我们尅设置某个IP范围走一个路由，其它走default路由。这样的话，有可能你好几个网卡的IP都可以通到外网。
结论：你可以通过netstat -r命令,然后找出路由表里面跟网卡IP同一个网段的所有IP，就是可能通到外网的IP，但不能保证路由表设置就是正确的，所以还要进一步逐一证实
就是在多网卡的情况下，多ip的情况下，怎么判断是哪个网卡ip连接着外网啦
------解决思路----------------------
把其他网卡关了，剩一个，哪个能ping通外网，那个就是外网的ip
------解决思路----------------------
要是route没配好,ping死都出不去....
------解决思路----------------------
http://hawknotes.blogspot.com/2010/06/finding-your-external-ip-address.html
#! /bin/bash
# Determine the public IP address for your DHCP system by bootstrapping
# calls to your gateway/router
# Requires "route," available in Ubuntu package net-tools, and
# nslookup, available in Ubuntu package dnstools
# Disclaimers:
# 1) This works with Verizon FIOS using the Actiontec MI424WR Router
# If you have another system YMMV.
#
# 2) And, as you'll no doubt note, this is set up for a Debian system,
# specifically Ubuntu 10.04 . Package names and installation
# procedures for other systems WILL vary.
#
###
# Start Here:
###
#
# Get Router internal Gateway IP
# Information found on
# http://www.cyberciti.biz/faq/how-to-find-gateway-ip-address/
# If route is not installed, run
# sudo apt-get install net-tools
# and make sure /sbin is in your $PATH
# Note "U" = up, and "G" = gateway
internalip=`route -n
------解决思路----------------------
grep UG
------解决思路----------------------
awk '{print $2}'`
echo Your Gateway\'s Internal IP Address is: $internalip
# Now we need to get the name of the router. If you don't
# have nslookup installed, run
# sudo apt-get install dnsutils
echo -n "Your Gateways's name is: "
routername=`nslookup $internalip
------解决思路----------------------
grep "name ="
------解决思路----------------------
awk '{print $4}'`
# On the Actiontec, at least, the name has an annoying "." at the end.
# Remove it:
routername=${routername%\.}
echo $routername
echo -n "Your Public IP Address is: "
nslookup $routername
------解决思路----------------------
grep Address
------解决思路----------------------
tail -1
------解决思路----------------------
awk '{print $2}'
------解决思路----------------------
这个问题有点复杂。
首先，如果只有一个链路可以通到外网的话，那么要看路由表的设置。如果路由表设置不正确，就连不上外网。一般的，就看default路由了，如果这个路由跟某个网卡上面的IP同一个网段，那么这个IP就是通向外网的那个IP了。
还有一种可能，就是有多个链路可以通到外网。其实我们每个PC，从某种角度来说，都是一个路由器，我们尅设置某个IP范围走一个路由，其它走default路由。这样的话，有可能你好几个网卡的IP都可以通到外网。
结论：你可以通过netstat -r命令,然后找出路由表里面跟网卡IP同一个网段的所有IP，就是可能通到外网的IP，但不能保证路由表设置就是正确的，所以还要进一步逐一证实