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How to get my dhcp ip address, whether i am in a local network?

I.e. if we have internet access in local network, but i want to know my dhcp server IP .. like " what is my IP" ..

Surender Chopra
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  • ifconfig gives informations about your network adapters. eth0 is the first (and probably only) ethernet adapter. It's current IP address is listed as inet address. – Nephente Sep 15 '15 at 05:45

2 Answers2

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Edit Your question was worded in slightly confusing way. Getting your public IP form terminal can be done with curl https://diagnostic.opendns.com/myip. Open DNS has web service that tells you your IP address, which is pretty much just a web page , with only one text - your IP. Effectively, you are downloading a web page that tells you your IP.

Original

Typically dhcp server is located on the router. Thus , your main goal then is to get address of the router, which in networking terms would be default gateway. Thus , effectively your question can be solved by the multiple solutions as described in my answer here. The simplest method is to use netstat -nr command.

There is another method as well: nmcli dev list | grep -i dhcp_server_identifier (Ubuntu 14.04 and earlier). Sample output for that would be:

$ nmcli dev list | grep -i dhcp_server_identifier                              
DHCP4.OPTION[13]:                       dhcp_server_identifier = 192.168.0.1

With Ubuntu 15.04 the nmcli version is different, hence you have to enter slightly different command:

nmcli dev show | \grep 'gw ='

Side note : grep in my install of 15.04 is aliased to grep --color=auto which prints colorized output. If we want just to see the particular lines, we need to use simple grep, which the forward slash instructs the shell to use.

Community
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Sergiy Kolodyazhnyy
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What is my ip shows you the public IP of your gateway. If this is what you are looking for you wan use:

nslookup myip.opendns.com
  • dhcp server is a different term from public IP address. The dhcp server is what assigns a local IP address to a machine. For example, if my IP address on the network is 192.168.0.69 then where does it come from ? From the router, meaning that dhcp server is located at address 192.168.0.1, which is router local IP. – Sergiy Kolodyazhnyy Sep 15 '15 at 05:51
  • I know, and you are totally right. Otoh, if you google 'what is my ip' you get your public ip address. In typical home broadband connections the router acts as a dhcp server and a gateway (as, most likely, you already know) so I think this is what OP was asking. –  Sep 15 '15 at 06:01