[BBWolf]

Hi!
I have a computer, connected to University's LAN (I live in student's home). Every student was assigned an IP which we are supposed to use. Sometimes I get an error "IP address conflict with another system on network" - the icon then shows as if I were still connected, but internet doesn't work. Sometimes it helps if I just log off from my Windows account, and log back in. Can anyone tell me what could be the problem?

[Partizaan]

Quote

Every student was assigned an IP which we are supposed to use

Somebody is using your ip. prolly to surf pron or so. Yust tel your administrator about it.
The fact u got an fixed ip is prolly for loggin purposes

ask him information about the proxy and if u can use it.

[gr33dy]

I assume you've done this already, but make sure you set up your computer to use the IP they gave you (Static). If you have checked "Obtain Automatically," school's the DHCP may be assigning you one that some other student already has. If you have it set to static already, perhaps they issued the same IP to more than one student?

[BBWolf]

I am using the IP I got, and I don't believe they gave the same IP to more students. But it is possible someone is using it anyway... Which I don't understand is: I get this error while I am already logged on the network, using it. It would seem logical, even if someone else would try to use my IP, it would not let him in... Since the IP already exists. I did a test with a friend, I tried to use his IP while he was logged, but it would not let me...

[BBWolf]

Anyone? Please? :unsure:

[skiddieleet]

That would seem logical. We have dhcp wireless at my school and it seems like I get that error a lot, but I never lose my connection. I would definitely let an admin know. He can watch for other people using your ip and do something about it. It is weird though that it kicks you off when you were the initial one to use it.

[shell6]

Forget what was assigned to you! Use a different IP! Even go to another net if you have to (ex, 192.168.1.20 was assigned to you so use 192.168.2.29 instead, etc)

[tuttefrut]

shell6, on Jun 26 2005, 11:02 PM, said:

Forget what was assigned to you! Use a different IP! Even go to another net if you have to (ex, 192.168.1.20 was assigned to you so use 192.168.2.29 instead, etc)

<{POST_SNAPBACK}>

i don't think that's a wise idea because the person that is using your ip might be doing some nasty surfing/downloading and then you will be responsible for it most likely :s

as said above, i also think you should notify the admin about ths issue

[tikbalang]

BBWolf, on Jun 22 2005, 06:41 PM, said:

I am using the IP I got, and I don't believe they gave the same IP to more students. But it is possible someone is using it anyway... Which I don't understand is: I get this error while I am already logged on the network, using it. It would seem logical, even if someone else would try to use my IP, it would not let him in... Since the IP already exists. I did a test with a friend, I tried to use his IP while he was logged, but it would not let me...

<{POST_SNAPBACK}>

report this matter to your administrator. if i'm not mistaken the error would give you what mac address of the other party in conflict . better report that too so help find out who uses your ip address.

as stated somewhere above, its probably being used for non acceptable manner. and if you dont report this matter immediately, you might be in trouble sooner or later.

having the same ip address on the network dont mean that you wont be able to login. the other party might not need to login to use your ip for what purpose.

the other party might not really be doing illegal things, but sort of denial-of-service attack on you. remember, your unable to use your internet access.

tikz

[BBWolf]

tuttefrut, on Jun 27 2005, 12:03 PM, said:

shell6, on Jun 26 2005, 11:02 PM, said:

Forget what was assigned to you! Use a different IP! Even go to another net if you have to (ex, 192.168.1.20 was assigned to you so use 192.168.2.29 instead, etc)

<{POST_SNAPBACK}>

i don't think that's a wise idea because the person that is using your ip might be doing some nasty surfing/downloading and then you will be responsible for it most likely :s

as said above, i also think you should notify the admin about ths issue

<{POST_SNAPBACK}>

I signed an agreement I would only use my IP ;)
Anyway, if it comes to this, I just change it to something else (some i know is not in use) and work with that one - untill I can use my own again. But that is exactly what I am afraid of - I may loose my internet access if the one using it does some nasty stuff :(

[BBWolf]

tikbalang, on Jun 27 2005, 12:34 PM, said:

BBWolf, on Jun 22 2005, 06:41 PM, said:

I am using the IP I got, and I don't believe they gave the same IP to more students. But it is possible someone is using it anyway... Which I don't understand is: I get this error while I am already logged on the network, using it. It would seem logical, even if someone else would try to use my IP, it would not let him in... Since the IP already exists. I did a test with a friend, I tried to use his IP while he was logged, but it would not let me...

<{POST_SNAPBACK}>

report this matter to your administrator. if i'm not mistaken the error would give you what mac address of the other party in conflict . better report that too so help find out who uses your ip address.

as stated somewhere above, its probably being used for non acceptable manner. and if you dont report this matter immediately, you might be in trouble sooner or later.

having the same ip address on the network dont mean that you wont be able to login. the other party might not need to login to use your ip for what purpose.

the other party might not really be doing illegal things, but sort of denial-of-service attack on you. remember, your unable to use your internet access.

tikz

<{POST_SNAPBACK}>

The error gives me just what I wrote here... I'm using winXP, so the error is just a baloon in the system tray... Is there a way I could get the mac adress anyway?

Anyway... If the person really is doing some attack, could a good firewall help with this? I'm using win XP's SP2 firewall - maybe that's not such a good idea?

[exp0sed]

BBWolf, on Jun 27 2005, 02:21 PM, said:

Anyway... If the person really is doing some attack, could a good firewall help with this? I'm using win XP's SP2 firewall - maybe that's not such a good idea?

<{POST_SNAPBACK}>

windows firewall is suitable for blocking connections but it wont tell you who is attempting to make a connection to your machine.. and anyway it sounds like someone is using an ip address assigned to you, not breaking into your machine. anyway, you also wont get their mac address unless you get it while your internet connection is working. you would need to use the nbtstat command but that would assume you knew the real ip address of the perpertrator. the other option is you may be able to install a sniffer and capture some network traffic but this may be against the university rules and you may get in trouble.

another question is how many network adapters are in your machine? is it possible the conflict is with your hardware? for example, 2 adapters trying to get the same ip address for an internal network? just a thought...

lastly... i would have to reiterate reporting the error to your admin. the admin will definately know the mac address of anyone attempting to access the network from any ip address. i would keep note of the times when you had the problem and the admin can then check those times against the logs to find out who is innappriately using your ip. you may also suggest that your admin use mac address filtering when assigning ips

good luck

-exp0sed

[beardednose]

HEre's what I did when this occurred on my network....

Open a command prompt and type:

nbtstat -A <ip address that is in conflict>

It will give you the NetBIOS name of the computer using that IP address as well as the domain that it belongs to, as well as the PC's MAC address. See below (no username shown):

NetBIOS Remote Machine Name Table

Name Type Status
---------------------------------------------
PC000848 <00> UNIQUE Registered
UNIVDOMAIN <00> GROUP Registered
PC000848 <20> UNIQUE Registered

MAC Address = 00-08-C3-B4-11-53

If someone is logged in, you will also get their user name.

Now you have something to go on. Either track it down yourself or give the info to your admin.