How to find IP on static network without DCHP

hglez86

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Apr 20, 2013
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I have a network with static IP addresses and I have the password. I would like to know how to find the gateway IP if I can't connect to the network because I don't know the IP range.
 

jackson1420

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May 10, 2010
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Your local private IP address or public IP?

Just type ipconfig in a command prompt

ifconfig if using unix/linux

ipconfig /all gives you more info but you shouldn't need that

And it is DHCP (Dynamic Host Configuration Protocol)
 

hglez86

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Apr 20, 2013
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You're right, DHCP, I got lazy after reading so much and not getting the answer X_x. Using ipconfig doesn't work, because since I'm not being assigned an IP the adapter takes that "preferred" they usually do when they don't receive a proper one from the router. I was thinking probably something like packet sniffing to see what range other computers use and then through that figure out what the router's IP address is or something. It's not my router, actually in my network I have the modem going to a router and I configured everything on it so I have no problem with that one :p
 
You might get it via packet capture but on a small quiet network you may have to wait quite some time. Generally the router will send out far more arp requests that anyone else. These are broadcasts so you will see them. If the subnet mask is not a common one it will take quite a lot of data to be sure you get it right
 

hglez86

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and would you need Wireshark or what program do you use for that? X_x I've heard a lot about it but haven't tried it... I wouldn't know how to start with the packet capturing X_x
 

jackson1420

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You don't need to make it complicated by getting packet tracing software.

What Operating System are you using?

ipconfig will still show your IP address even if it is static.

Wireshark is for network administrators really. Not needed to find a nodes address or gateway. I would be fired from my job (I work in IT) if I told my boss I am running Wireshark to find a my nodes IP address.

Your IP address will be displayed like this if using Windows (I am using a static IP):

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Link-local IPv6 Address . . . . . : fe80::fdbf:e50e:fae:1ef4%11
IPv4 Address. . . . . . . . . . . : 192.168.1.100
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1


A preferred address is an address that has been assigned to an interface and that can be used without any restrictions. So it has nothing to do with static vs dynamic IP addresses.

Typing ipconfig /all yields the (preferred address) which just signifies it is uniqueness on the network. This can be in an "Invalid" and "Tentative" state by the lease of you DHCP address is expired or being verified. I hope that helps. Let me know if I should clarify further :)
 
All you really need is winpcap that does the capture itself but wireshark makes life much easier. Since you are only capturing your traffic and you do not have a IP you will only see broadcast. It will be almost no traffic. You are looking for ARP messages.

To the above post...how else are you going to do this if DHCP is disabled and there is no static IP configured. This is a common problem when someone configures their router without DHCP and sets the lan address to something by mistake or forgets. How else do you get back into the router without factory reset....This method works but is tedious.
 

jackson1420

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I see the issue. Is there a reason you can't just reset the router? Is the configuration that important to keep?

Try Wireshark or winpcap which is the utility mainly used. The issue is you tell Wireshark to sniff for packets on the adapter which isn't configured to transmit traffic to the correct network.
 

hglez86

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Apr 20, 2013
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Keeping the configuration is important to my friend. He paid someone to have everything setup, so it's like something he has on a glass box now. He says that since he gave me the password he sees no use in letting me get to the router :p I can't get him to understand that X_x. at home I'm fine with my network, but when I go to his house I'm disconnected from the world(at least it feels that way :p)... so ipconfig doesn't show the right info because I haven't been assigned anything... I have to figure out what the gateway address is and that would tell me what range the IP I could use would be on too... I'll look into wincap, never heard of it before... and I'll get back to you next week... I have to go to the city I work at in like 30 minutes... and be disconnected from the world again X_x Thanks for the help so far, let's hope it works X_x
 

jackson1420

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Does the router have console ports?

Can you not look at any of the network's clients and see what IP they are using and match that? Or did the guy just set up the router with no DHCP and no other way to get in the router and left him without describing the most basic thing of a network. The IP configuration.

Find out what type of configuration is so important to keep. It is sometimes nice to update and go over all the features new and old.

Should ask for a refund or the IP configuration info because there are too many networks to try and you have to reset it or try basic IP networks... but who knows what he used if it is even a class C network or B or A... gives me a headache to think of trying even the common ones..
 

hglez86

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I know right? But I guess he just didn't know what to ask for. The only thing he ever uses is his tablet and his cellphone... and he won't let me see either one because they are his "precious" X_x
 
If you install wireshark it will install winpcap. Wireshark does not actual capture the data it just formats and displays it. It calls winpcap to actually collect the data. I would not try to use winpcap directly as you first go at capturing data you really have to know what you are doing to get anything useful out of it without other software. It does what tcpdump does in linux.
 

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