Dhcp Hangs Up

[raro]

Server and laptop both run on Win XP.

Server is connected to the internet and has a wireless card that serves as accesspoint.

If everything works well, the laptop finds the server, gets an 193.168.0.xx IP address and is connected.

Some times though, the DHCP seems not to work properly and the laptop gets an 193.168.177.xxx address. The subnet mask is then set to 255.255.0.0.

Is there a way to restart the DHCP service without restarting the computer?

[RKASA]

open the local connect status and click support and repair tab it should rerun the dhcp.

[technocracy]

Start menu

Click 'Run...'

enter 'cmd' press enter

at the prompt type 'ipconfig /release' and press enter

now type 'ipconfig /renew' and press enter and it will attempt to get a new IP Address via DHCP.

Edit: Also do you have security configured on the wireless? Since XP has a bug in SP2 that sometimes causes DHCP issues with WEP and WPA.

Edited August 21, 2007 by technocracy

[Guest Reimar]

If you're on WiFi you may have some neighbour with WiFi als well and the signal is better than yours. So may you Laptop connects to the other access point?!

I had that in the past in my Moban until I found out who was using WiFi near my house and told him to "secure" him system and not let anyone connetc to it! Since them no more problems!

[RKASA]

use the start>connect to>wirerless connection. When the icon shows in the task bar click on it. it will show you all the availble signals and yours. make sure your connected to your network. Or if you want to download porn connect to theirs

[raro]

Start menu

Click 'Run...'

enter 'cmd' press enter

at the prompt type 'ipconfig /release' and press enter

now type 'ipconfig /renew' and press enter and it will attempt to get a new IP Address via DHCP.

Edit: Also do you have security configured on the wireless? Since XP has a bug in SP2 that sometimes causes DHCP issues with WEP and WPA.

thanks for all your answers!

the "repair" function I tried earlier, no avail.

Technocracy: The ipconfig commands...do I do that on the server or the laptop? Your edit seems to be the key to the solution. My wifi is secured, afterall I need the full bandwidth for my own porn downloads... ....any solution for that SP2 bug?

I have no other wifi connections in the area...this I have in the office, though. There I encountered serious problems with the wifi connection until I switched to a different channel.

[RKASA]

I don't see a reply from Technocracy for you so I would like to say run the ipconfig from the command line

use start> run on the promp type in ipconfig/release ect like in his post. It may in fact work better then repair, repair may not be releasing the IP before repairing the connection. edit:I am soorry he did say all that. Run it on the device which your connecting ie the laptop

Edited August 23, 2007 by RKASA

[raro]

ok, thanks! will try next time

[technocracy]

Start menu

Click 'Run...'

enter 'cmd' press enter

at the prompt type 'ipconfig /release' and press enter

now type 'ipconfig /renew' and press enter and it will attempt to get a new IP Address via DHCP.

Edit: Also do you have security configured on the wireless? Since XP has a bug in SP2 that sometimes causes DHCP issues with WEP and WPA.

thanks for all your answers!

the "repair" function I tried earlier, no avail.

Technocracy: The ipconfig commands...do I do that on the server or the laptop? Your edit seems to be the key to the solution. My wifi is secured, afterall I need the full bandwidth for my own porn downloads... ....any solution for that SP2 bug?

I have no other wifi connections in the area...this I have in the office, though. There I encountered serious problems with the wifi connection until I switched to a different channel.

Apologies I forgot about this thread

As has been said you issue the ipconfig commands on which ever PC you want to get a new address on.

As for Microsoft bug - I believe it will be fixed in SP3 (but it could of been fixed in the interim, however my wireless equipment is in the UK and I ain't shipped it yet so I can't check) - I believe the problem affects WEP more than WPA2 - so if you're using WEP change to WPA (which ideally you should be)

As for checking what other other wireless Access Points (routers) are around your neighbourhood and also to check if you are conflict channels (remember if you are using 802.11b or g you need 5 clear channels between other signals. Download Netstumbler and become enlightened as what is around you!!

Netstumbler Download

The recommended channels are 1, 6, 11 - although this is mainly due to a US RF signal restriction which states only channels upto 11 can be used. In Thailand you can obviously ignore this and use channel 12 through to 14 as well, although be aware that some devices don't actually support them due to being made for the US market.

Have fun!

Edited August 24, 2007 by technocracy

[raro]

the DHCP hung up again and I did the ipconfig /release and /renew routine on the laptop. Produced this error message:

I understand that the DHCP does not exist anymore, so the problem seems to be rather with the server than with the laptop.

Again, there are no other WiFi networks around.

Over to the Nerds! (Monty, where are you when we need you? )

[Pomthai]

I get this with vista on one machine and xp on another, both wireless laptops. The only solution I found was to leave the router set as before and set static IP addresses for the two computers. It only hassle with this is if you connect to a hot spot or somewhere else with one of the laptops you have to remember to set it to automatically find the IP address again.

[raro]

right, once I set the laptop to a static IP the problem is solved. BBut as you said it is a pain when you go to hotspots or as in my case to the office where I have a different IP envirnonment (192.168.5.xxx).

Anyways, this cannot be the solution....is the DHCP just hanging up? I googled on the subject but could not find anything that I would understand....too much Nerd languange....

[stumonster]

another article about vista not working correctly with linux DHCP servers made me think of this thread.

http://www.neoseeker.com/news/story/7081/

raro,

just to get my head around your configuration.

you have a desktop connected by ethernet ( rj45 ) to your ADSL/cable modem and also have a PCI wifi card in it.

you are using windows "internet connection sharing" on the desktop.

you connect to the desktop via wifi from your laptop to access the internet whilst you are at home.

is that correct ?

[raro]

another article about vista not working correctly with linux DHCP servers made me think of this thread.

http://www.neoseeker.com/news/story/7081/

raro,

just to get my head around your configuration.

you have a desktop connected by ethernet ( rj45 ) to your ADSL/cable modem and also have a PCI wifi card in it.

you are using windows "internet connection sharing" on the desktop.

you connect to the desktop via wifi from your laptop to access the internet whilst you are at home.

is that correct ?

Hi Stumonster, almost...I use a USB ADSL Modem, but that should not make any difference. Both computers run on XP Pro, no Vista as I don't use M$ products that are not past their second service pack I also don't use Linux as I am too stupid to do so...tried recently Ubuntu but it doesn't find the USB modem and no idea how to configure that...

I am pretty much convinced that the DHCP on the desktop hangs up. When I bring my laptop without restart to the office, it finds the wireless network there and connects without problems.

Back to the original question: Is there a waty to restart the DHCP WITHOUT restarting the computer?

I am pretty much conv

[Simmo]

I have this problem all the time at the office with various laptops and PDA's. It's definitely got to do with using WEP encryption & DHCP. Once you power off / on the wireless access point it's fine for awhile.

Got so annoying I switched the wireless access point to open with MAC address filtering on. Never been a problem since then.

[technocracy]

I have this problem all the time at the office with various laptops and PDA's. It's definitely got to do with using WEP encryption & DHCP. Once you power off / on the wireless access point it's fine for awhile.

Got so annoying I switched the wireless access point to open with MAC address filtering on. Never been a problem since then.

I hope you don't mind other offices or people using your wireless!

Change from WEP to WPA like I said previously. WPA is more secure - in a busy environment you can hack a WEP key in a few minutes, it's very simple.

The issue as stated by Simmo again is 100% to do with the wireless encryption and dhcp in Windows. It's a pain in the butt and microsoft just don't seem to be arsed about fixing the issue yet.

[raro]

The issue as stated by Simmo again is 100% to do with the wireless encryption and dhcp in Windows. It's a pain in the butt and microsoft just don't seem to be arsed about fixing the issue yet.

...there we go again...

ok...thanks for all your input, looks as we can't solve it here thanks to M$'s customer ignorance...

[Simmo]

I have this problem all the time at the office with various laptops and PDA's. It's definitely got to do with using WEP encryption & DHCP. Once you power off / on the wireless access point it's fine for awhile.

Got so annoying I switched the wireless access point to open with MAC address filtering on. Never been a problem since then.

I hope you don't mind other offices or people using your wireless!

Do you know what MAC filtering is .....

Change from WEP to WPA like I said previously. WPA is more secure - in a busy environment you can hack a WEP key in a few minutes, it's very simple.

The issue as stated by Simmo again is 100% to do with the wireless encryption and dhcp in Windows. It's a pain in the butt and microsoft just don't seem to be arsed about fixing the issue yet.

Good luck getting WPA working on win 2000.

[technocracy]

I have this problem all the time at the office with various laptops and PDA's. It's definitely got to do with using WEP encryption & DHCP. Once you power off / on the wireless access point it's fine for awhile.

Got so annoying I switched the wireless access point to open with MAC address filtering on. Never been a problem since then.

I hope you don't mind other offices or people using your wireless!

Do you know what MAC filtering is .....

Change from WEP to WPA like I said previously. WPA is more secure - in a busy environment you can hack a WEP key in a few minutes, it's very simple.

The issue as stated by Simmo again is 100% to do with the wireless encryption and dhcp in Windows. It's a pain in the butt and microsoft just don't seem to be arsed about fixing the issue yet.

Good luck getting WPA working on win 2000.

Do you know how easy it is to find out the allowed MACs and configure your PC to have the same MAC? Oh it takes the entirety of 30 seconds maybe 1 minute even less than cracking WEP which is easy enough.

Answer to your question yes and I know exactly how big a security risk it is relying on it. I have designed many wireless installations and written security policies for several MNCs - so the answer to the question is - sure do!

Do I often go to Bangkok and get free internet in hotels from the generous people in office and shops around me . . . sure do!

Oh and by the way disabling SSID broadcast doesn't help either all that does is stop a wireless client in window from see it and trying to connect automatically - open up and wireless sniffer and you'll see that the SSID is in all data packets sent from the access point . . . the only real way of being secure is stopping people from being able to gain access in the first place. Primarily using security and encryption or physically by using directional antennas and minimising the signal from flood out the building.

Also using MAC filtering only give people a minor headache in attaching to the LAN - but then again they don't need attach really since they could capture all your traffic and details that are being sent through the air completely unsecured. Much like people do in airports . . . never log into your bank accounts via a free wireless internet link in such a public place.

I sat in BKK Thai lounge not that long ago and decided to see what was in the air - and from turning my sniffer within about 2 minutes had the contents of some unexpecting person gmail account. I didn't read them or care but it was just a check from a professional view people to see how lax people are.

[raro]

Technocracy: You scare me! I always work from my laptop, at home and in the office. I am always connected by WiFi as I hate cables with a passion (hope they will have wireless electricity any time soon...)

Anyways, just checked the WiFi configuration on the server and I cannot find anything about WEP and WPA...settings are:

Network Authentication: Open

Data Encryption: Disabled.

There is a network key, but it is grey and cannot be edited.

The whole Authentication tab cannot be edited, because of ad hoc network.

[technocracy]

Technocracy: You scare me! I always work from my laptop, at home and in the office. I am always connected by WiFi as I hate cables with a passion (hope they will have wireless electricity any time soon...)

Anyways, just checked the WiFi configuration on the server and I cannot find anything about WEP and WPA...settings are:

Network Authentication: Open

Data Encryption: Disabled.

There is a network key, but it is grey and cannot be edited.

The whole Authentication tab cannot be edited, because of ad hoc network.

You've not got any encryption enabled - which means your DHCP problem is something else - I didn't see anywhere that you were using a adhoc network. It could well be the fact that there is some kind of interference from another wireless devices (I don't know where you are or you neighbourhood) - have you downloaded Netstumbler and checked out what other wireless networks are around you? You should do this first since it does sound as this is a transmission problem rather than server issue. Also don't rule out thing such as baby monitors or mobile house phones, if any are around check there what frequency they use - if they use 2.4Ghz this is the same as the commonly use 802.11b/g wireless and not good a thing as they could be interferring.

Ideally you should enable WPA encrpytion - to do this click on the drop down arrow by the Network Authentication you should see the option of WPA-None - click this. Then the Data Encrpytion option will change to TKIP click on the drop down arrow key here and all being well there should be a AES option - click this.

AES may not be there it depends on the software and you wireless card - due to additional processing of AES encryption it's not always supported. Otherwise TKIP is fine.

Now enter a nice long random network key - remember to write it down! Then click OK.

Next configure your other PC exactly the same.

Hey presto you and all you communications are secure - well as secure as you've made your key! Traffic encrypted with AES is extremely secure as the AES encryption is unbreakable - TKIP isn't as secure but is hasn't any known weakness either.

The only thing with using a static network key is you need to make it a random and long string of characters for it to be 100% secure - to stop dictionary attacks if you use say - 'house' as your key it would take long for someone to perform a dictionary attack and find it.

As for scaring people . . . sorry . . . I scare people for a living with wireless by showing them just how unsecure there data/network is!! People have this strange idea just because wireless is easy to setup it's a simple technology and do not have concerns over security, I just give people a wake up call when required!

[stumonster]

Do you know how easy it is to find out the allowed MACs and configure your PC to have the same MAC? Oh it takes the entirety of 30 seconds maybe 1 minute

but then after you had sniffed the MACs you would have to wait until that MAC was not being used, so you could spoof and connect.

I sat in BKK Thai lounge not that long ago and decided to see what was in the air - and from turning my sniffer within about 2 minutes had the contents of some unexpecting person gmail account. I didn't read them or care but it was just a check from a professional view people to see how lax people are.

and if the person had logged on to https://mail.google.com/ as they should have while using a wifi access point ?

if your data is that important I don't think you should be using WiFi.

[RKASA]

If I am reading this right OP has problem with the ad hoc, maybe should just get an AP or use a switch. Seems windows can't even play with itself.

[technocracy]

Do you know how easy it is to find out the allowed MACs and configure your PC to have the same MAC? Oh it takes the entirety of 30 seconds maybe 1 minute

but then after you had sniffed the MACs you would have to wait until that MAC was not being used, so you could spoof and connect.

I sat in BKK Thai lounge not that long ago and decided to see what was in the air - and from turning my sniffer within about 2 minutes had the contents of some unexpecting person gmail account. I didn't read them or care but it was just a check from a professional view people to see how lax people are.

and if the person had logged on to https://mail.google.com/ as they should have while using a wifi access point ?

if your data is that important I don't think you should be using WiFi.

Firstly you don't have to wait for a MAC not to be used a standard AP wouldn't know if there is two devices using the same MAC (it can't tell the difference). That is what you need a WIDS for these will report duplicate MACs and shutdown the ones that appear after the original. Duplicate MACs don't mean much in Wireless since you aren't physically connected to the devices so it has no way of recording where it first saw the MAC unlike wired switches.

Secondly, it is only the front page that uses TLS once they are logged in it reverts to clear text and that is what the emails are sent over.

If your data is important you need a decent wireless security setup. Wireless can be as secure as any other media it just needs a bit more work. In general for most remote workers they'll use an encrypted VPN tunnel to connect to the office thus meaning all traffic to and fromt the office is protected.

[monty]

Just forget the dhcp...

I only have a dhcp server enabled at my place so visitors with their laptops can connect easily on the wifi.

All my other equipment (quite a lot of it!) has fixed IP's, and I have nice map indicating what equipment is where what IP address I assigned to it. Nothing much to go wrong, never any conflicts and easy to troubleshoot.

Now to help out Raro, I would advice him to do the same, put everything on fixed IP addresses.

Then download a little program called netsetman (find it here).

This lovely free utility lets you preset up to 6 different network settings (IP, gateway, dns...), along with for example network printers and even your pc name and workgroup. It puts a little icon in your taskbar, click on it and you can instantly switch between any of your 6 settings. Make one for home, one for the office, another one for public hotspots (just set that one to search for dhcp server)...

[raro]

Hi Monty, just want to say thanks for this wonderful tool! Once it is set up, working with a laptop in various locations has become soooo easy! The Wifi connection is much more stable and faster, even at home with my old 11 Mbps access point I have streaming videos on the laptop! Highly recommended!!