[SOLVED] Which ip is on work now?

luofeiyu · 11-21-2015, 07:23 AM

Here is my /etc/network/interfaces file.

Code:

auto wlan0
iface wlan0 inet manual
wpa-driver nl80211
wpa-roam /etc/wpa_supplicant.conf
iface default inet static
address 192.168.1.101
netmask 255.255.255.0
gateway 192.168.1.1
dns-nameservers 192.168.1.1
if-up ifconfig eth0 down

The info display on the screen when to input 'ifconfig'.

Code:

eth0      Link encap:Ethernet  HWaddr e0:3f:49:57:4b:d1  
          inet addr:192.168.1.3  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::e23f:49ff:fe57:4bd1/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:6068 errors:0 dropped:0 overruns:0 frame:0
          TX packets:113 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:3780468 (3.6 MiB)  TX bytes:11800 (11.5 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:14 errors:0 dropped:0 overruns:0 frame:0
          TX packets:14 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:700 (700.0 B)  TX bytes:700 (700.0 B)

wlan0     Link encap:Ethernet  HWaddr 00:21:5d:26:c1:10  
          inet addr:192.168.1.101  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::221:5dff:fe26:c110/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1291 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5146 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:81917 (79.9 KiB)  TX bytes:992000 (968.7 KiB)

Now i am cofused that which ip is mine ?192.168.1.3 or 192.168.1.101
Which one is at work ?192.168.1.3 or 192.168.1.101

pan64 · 11-21-2015, 07:49 AM

most probably both are available. You need to check your route config to see which one is the preferred (execute the command route)

luofeiyu · 11-21-2015, 07:58 AM

route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.1.1 0.0.0.0 UG 0 0 0 wlan0
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
192.168.1.0 * 255.255.255.0 U 0 0 0 wlan0

onlyonemac · 11-21-2015, 02:05 PM

You have two IP addresses. One refers to your ethernet card and the other refers to your wireless card. Which card is used by default depends on your configuration (it's usually the ethernet card if it's available).

luofeiyu · 11-21-2015, 08:04 PM

Do two ip addresses can be used at the same time?
How can i make wlan0 be defaultly active ?
Which ip is being used when to connect to http://www.linuxquestions.org

berndbausch · 11-22-2015, 01:04 AM

Quote:

Originally Posted by luofeiyu

Do two ip addresses can be used at the same time?
How can i make wlan0 be defaultly active ?
Which ip is being used when to connect to http://www.linuxquestions.org?

First question: Yes.
Second question: Depends on your distro. Yours seems to be Debian-based, so look for advice on help.ubuntu.com, or the Mint wiki, or the Debian wiki.
Third question: This depends on your routing table. Your routing table indicates that you will use wlan0:

Code:

Destination Gateway     Genmask        Flags Metric Ref Use Iface
default     192.168.1.1 0.0.0.0        UG    0      0   0   wlan0
192.168.1.0 *           255.255.255.0  U     0      0   0   eth0
192.168.1.0 *           255.255.255.0  U     0      0   0   wlan0

Since the IP address of linuxquestions.org is not in the 192.168.1.0/24 range, the default route will be used.

berndbausch · 11-22-2015, 01:07 AM

Quote:

Originally Posted by berndbausch

First question: Yes.
Second question: Depends on your distro. Yours seems to be Debian-based, so look for advice on help.ubuntu.com, or the Mint wiki, or the Debian wiki.
Third question: This depends on your routing table. Your routing table indicates that you will use wlan0:

Code:

Destination Gateway     Genmask        Flags Metric Ref Use Iface
default     192.168.1.1 0.0.0.0        UG    0      0   0   wlan0
192.168.1.0 *           255.255.255.0  U     0      0   0   eth0
192.168.1.0 *           255.255.255.0  U     0      0   0   wlan0

Since the IP address of linuxquestions.org is not in the 192.168.1.0/24 range, the default route will be used.

If you want to learn about networking, there are many tutorials out there. One that I happen to know about is http://www.linuxhomenetworking.com, though it doesn't seem to be well maintained.