Strange DHCP occurances?
Gday,
I have just had a strange occurance to my home wireless network overnight.
Up until yesterday all wireless connected devices, ie, laptops x 4, where all associating and obtaining an ip address, gateway & DNS's without an issue, this morning my daughter complained that the internet was not working. Upon investergation I noticed that her laptop had obtained the ip address in the range 192.168.0.x. My home network is in the 10.1.1.x range.
Then the other daughter complained of the same thing, and her's had also obtained this 192.168.0.x range ip address.
Further looking, both my 2 laptops where in the same boat.
The fix was to set IP, netmask, gateway & DNS's manually.
But this did not explain why the DHCP was not allocated at boot time??
The router is a Netgear DG843G Adsl/Switch & wireless modem all in one.
It appears to all be working fine, DHCP server is ticked with the range 10.1.1.100 to 10.1.1.125.
I disabled and re enabled to no avail.
3 of the laptops run Vista and one runs XP SP3.
A google search reveiled several leads and possible fixes, fixes dated back in 2007. I am reluctant to try these fixes just yet, wondering why, after several years of laptop wireless networking in the house that it deceides to start to stuff up now????
I am at a loss to explain why, although fixed through static settings, it is NOT how I wish to run my wireless segment of my LAN.
I have checked that there is not a 2nd DHCP server running on my LAN, and there is not.
So, any ideas?
Thanks for your assistance.
Porkop
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192.168.0.xxx and 192.168.1.xxx are common address ranges for wireless network devices.
Perhaps a neighbour has a wireless network using this address range.
It sounds as if your computers all locked on to another nearby wireless device (wireless router, access point etc.).
This can happen if your DHCP server loses power or the radiated signal is reduced for some reason.
The best way to avoid this is to ALWAYS manually allocate your own unique (fixed) IP addresses and not use DHCP.
Manually allocated IPs are not better or worse than DHCP system
If you manually allocated ensure that you exclude these addresses from the DHCP server otherwise another machine will be allocated.
What do you have under Network Configuration/internet protocol TCPIP/Alternative Configuration
To fix the IP address if it is incorrect you need to release the current IP address. This can be done manually (Command prompt ipconfig /release /all) or doing a repair on the network connection.
As to why the system allocated a different address.
If the alternative configuration is configure for NOT private address then a 168.... address should have been assigned.
If they were allocated a IP address from another DHCP client then the lease would need to expire before a new IP address would be looked for.
hasnt failed me for years, why start now, that is my question.Originally Posted by tristen
Manually allocated IPs are not better or worse than DHCP system
agree, I have (had) a mixture of static and dynamicily allocated ip addresses, the dynamic range inmy case (10.1.1.100 to 10.1.1.125) allowed for not only my families laptops but those of visiting friends and relo's to easily link into my system, after entering the security key that is. Itis just the way I wanted to do it
If you manually allocated ensure that you exclude these addresses from the DHCP server otherwise another machine will be allocated.
already did that
What do you have under Network Configuration/internet protocol TCPIP/Alternative Configuration
To fix the IP address if it is incorrect you need to release the current IP address. This can be done manually (Command prompt ipconfig /release /all) or doing a repair on the network connection.
done it all, as I said I know my way around and have tried all the tricks to get it to work, execpt of course the actual fix, which is unknown at this time.
As to why the system allocated a different address.
If the alternative configuration is configure for NOT private address then a 168.... address should have been assigned.
If they were allocated a IP address from another DHCP client then the lease would need to expire before a new IP address would be looked for.
again, agree. I can not see any alternatice dhcp server on my network. It has me stumped.
Normally, from my experience, when a wireless client is unable to obtain an ip address from its connected network it normally has a default ip address in the 169... range, I have seen this several times on both wired and wireless systems. But in this case, 182.168.0.x???????
At first I thought it may have come from the linux system on the eth0 card (eth1 being my local LAN, wireless LAN and internet segment) that is connected to the melbourne wireless network but the linux system was not on at the time.
mhhhhh
ps. One thought is that the system is trying to obtain an ip address before the network manager has had an opportinuity to connect to the access point, and a timeout situtation occurs and defaults are loaded????? I have noticed over the last few months that with each microsoft update the systems here become more and more bogged down at boot time? and YES, I scan with Awaware, Spybot S&D, Malwarebytes, AVG or Avast (different pc have different virus scanners) and Ccleaner on weekly basis's
Last edited by porkop; 20-04-09 at 02:22 AM. Reason: after thought
Ok, problem solved. I had inadvertantly issues a static IP address to a network printer in the range set aside for my mobile/portable network devices (laptops). This was preventing devices from aquiring an ip address from the dhcp server as the printer was reporting that "that ip address is in use" error. But, I still feel it strange that the network was working for a few weeks before this issue raised its head?????
anyway, fixed. I moved the dhcp allocation range away from the printers ip address, was easier to do that than have to change the printer and update all the computers with its new details.
Good to hear you found the issue
odds are the delay was due to the expiring of the DHCP lease period.
most probaly. anyway, I can stick all that hair back in my head lol
Strange DHCP occurance
That still doesnt explain where you were getting the 192.168.0.x addresses. The static address you had on your printer would have rendered either the printer or the computer that the printer was sharing the ip address with as not connected and you would have also got a ip address in use error on your MS or Mac desktop. The address range you were getting is what Linksys wireless routers generally allocate so it sounds like the problem was more then likely what was mentioned earlier ie connected to a unsecure network.
As long as its working now guess it doesnt matter.
ikhan42
you are right. It does not explain it. I still doubt that there was an association with a different wireless router as the profile still stated that it was associated with my ssid.
Linksys arent the only ones that used the class C ip range of 192.168.0.x, in fact the majority of wireless routers I have had experience with have this range, netgear, dlink, linksys, cisco, and a few others.
I dont think I will bother getting another headache thinking where the ip allocation could have come from as it is all back to how it should be which was my aim.
That being said, all of those that had input, I thank you. As always, there is a wealth of experience and information available to all of us here on Austech and I appreciated my drawing upon it this time.
regards
porkop
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