0

I need to figure out some way to allow my computer to get assigned a specific IP address. This IP is already taken by some other device on the network. The network is laid out with Source > Firewall/Filter > Switch > Switch > Computer. I have done some research and found out how to scan for IP addresses, but, being the novice that I am, I have no idea how to identify what device is using the desired IP address and I have no way to get DHCP to reassign a new one for it so that my computer can have the IP instead. Basically, I want a static IP in the midst of all the other DHCP IPs. I have tried to simply change my computer's IP, and it results in a loss of internet access until I re-enable DHCP. The DHCP Server is dynamically allocated. I am not the system administrator, but I work for someone who is, and I have the admin passwords.

Apologies if any of the given information is hard to understand or even completely incorrect. I am working off of the limited existing knowledge that I have, and that's not a lot. I will edit my question if any further information is needed.

2
  • 1
    use arp -a command to find out who (hardware address) has what ip address (logical address). Also you should specify your OS in the tags as it might be usefull for your case/question down the road.
    – mnmnc
    May 31, 2017 at 14:07
  • You should modify your DHCP configuration on the Switch to always assign the same ip address to that specific device then simply restarting the DHCP service on the Switch will resolve your conflict.
    – Ramhound
    May 31, 2017 at 14:09

1 Answer 1

0

You need to configure the DHCP server to reserve the address for your computer. There simply is no way to do this from the client.

While you can often, software permitting, set any arbitrary IP address to a specific device, it is more typical to assign a DHCP range and then set static IPs outside of this range e.g. dhcp range is x.x.x.10-100; static addresses x.x.x.101-254

5
  • @joshua-minett i think I might disagree with that statement that it is impossible from client side. Consider arp spoofing + arp flood to legitimate host that occupies desired IP address - this should lead to ip spofing with issuing command for DHCP IP lease renewal with new MAC address. I think this might lead to DHCP server issuing IP address to user computer. Stopping the flood will cause legitimate host to get a message that this IP is already taken - or am I mistaken?
    – mnmnc
    May 31, 2017 at 14:18
  • IP spoofing is not going to get you a static address, nor is it going to be reliable. ARP flood, spoofing, etc. might fit the bill, but is akin to setting the house on fire to let in some fresh air. I presumed the OP wanted it done correctly, but this is not certain.
    – Yorik
    May 31, 2017 at 16:22
  • The method you have described would work fine. I don't mind if there is any message popping up on the original host computer. However, I need to be sure that the IP stays set on my computer permanently. I don't need to do it from the client side necessarily, as I have admin access to the server computer. A couple questions though: What if the IP I need/want is in the DHCP range? Also, how would I go about reserving the IP from the server? May 31, 2017 at 17:04
  • @JoshuaMinett: that is a software question: different routers/firewalls/DHCP servers have different ways to do this in the GUI or console. Some you simply find the device, check "make permanent lease" and apply.
    – Yorik
    May 31, 2017 at 17:12
  • What about having a static IP in the DHCP range? May 31, 2017 at 17:35

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .