I have a home network consisting of a Westell DSL modem/router, an Asus mb Desktop, Toshiba Laptop, another desktop (Wife's), a HP3200 printer and an HPC309a printer. The printers are connected thru an ehternet switch to the router. The Laptop and Wife's are running Win7 Home Premium, the Desktop is running Win7 Pro. When the C309 is disconnected all is well I have no problem with connecting to the internet with any machine. When the C309 is connected (or turned on if off) in a short time my desktop loses internet connectivity. The other 2 machines are not affected, they get DNS via the router. At the desktop, I have tried various DNS sources, my ISP's, open DNS, Microsoft's, the router, it makes no difference. I can ping my ISP's and get a response but nslookup only returns a no response, somehow the DNS requests are being blocked. If I put Desktop to sleep and bring it back again DNS will work for a while. If I turn off the printer, sleep and return the problem is gone. I figure that since only the Pro is affected, I must have one of the networking features that exist only in Pro set wrong. Has anyone any ideas?

Are you sure that the Windows 7 machine isnt only affected by DNS? Is there network connectivity avaiable? Can you ping the other computers by IP address when this happens? Have you verified that the Win 7 computer and the printer are simply using the same IP address (Ip conflict). It may help if you post the results of the Win 7, IPCONFIG /ALL and that of the printer device to compare. Visit: anITKB.com, an IT Knowledge Base.

I should have added more detail. Applications with internet access continue to run, I just can't start any more unless I can supply the numerical address. I can talk to the printers (on IE I have favorites that use the numerical address). I tried putting the C309 address outside the router DHCP range, no difference, addresses do not conflict, have shutdown Antivirus and firewall also. Interesting that it's the newer, more network elaborate printer (C309) that is causing the problem. I have run out of time today but will post the IPConfig and other info tomorrow. Thanks for the help.

Interesting... that your Win 7 client DNS client encounters issues when the printer is online. It doesnt make sense at the moment. There is something else going on. The IPCONFIGs may shed some light... Visit: anITKB.com, an IT Knowledge Base.

OK, here is the router assignments: Name: LAPTOP wireless Type: Computer Connection: Ethernet IP Address: 192.168.200.62 Name: C309 Wired Type: Printer Connection: Ethernet IP Address: 192.168.200.104 Access Shared Files Access Device Name: HP3210 Type: Printer Connection: Ethernet IP Address: 192.168.200.83 Access Shared Files Access Device Name: DLink Wireless Type: Router Connection: Ethernet IP Address: 192.168.200.2 Access Device Name: LAPTOP ethernet Type: Computer Connection: Ethernet IP Address: 192.168.200.26 Name: Desktop Type: Computer Connection: Ethernet IP Address: 192.168.200.53 Access Shared Files Note that C309 is off line (turned off). Here is the IPConfig for the 7 Pro: C:\Windows\system32>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : Desktop Primary Dns Suffix . . . . . . . : Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : DSL Router Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : DSL Router Description . . . . . . . . . . . : NVIDIA nForce 10/100/1000 Mbps Ethernet Physical Address. . . . . . . . . : 00-24-8C-45-1E-42 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::c55d:d109:f864:6e89%11(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.200.53(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 192.168.200.1 DHCP Server . . . . . . . . . . . : 192.168.200.1 DHCPv6 IAID . . . . . . . . . . . : 402662540 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-12-7E-35-37-00-24-8C-45-1E-42 DNS Servers . . . . . . . . . . . : 192.168.200.1 72.235.80.4 NetBIOS over Tcpip. . . . . . . . : Enabled Tunnel adapter Teredo Tunneling Pseudo-Interface: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv6 Address. . . . . . . . . . . : 2001:0:4137:9e76:3cef:1d30:3f57:37ca(Pref erred) Link-local IPv6 Address . . . . . : fe80::3cef:1d30:3f57:37ca%14(Preferred) Default Gateway . . . . . . . . . : :: NetBIOS over Tcpip. . . . . . . . : Disabled Tunnel adapter isatap.DSL Router: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft ISATAP Adapter #4 Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes C:\Windows\system32> The IPconfig for Laptop has wireless LAN as well as ethernet. The ethernet is similar to Desktop except for physical addresses, IP addresses and the DNS is coming from the router. I turned on the printer and will run another IPConfig when I lose the DNS. I have to send this one now, don't want to lose it!

It took awhile, I did some printing and then I could no longer access web pages. I could ping my ISP's DNS servers, the 4.2.2.2 server but when I did an NSLookup I got "no response from server". I did an IPConfig /all and got an identical one to what I sent you. BTW I'm using the Laptop now since I can't get back on the forum with the desktop. Normally during the day I have a stock market feed running and news on IE8. When the DNS access quits, the market feed and news are still there. Running the trouble shooter tells me to reset my modem but that's not right since both data is coming in to my Desktop and all is working fine on the laptop. (I have the other computer shut down to keep things simpler). I seems like the problem may be in the extra networking features that come with the Pro and are not in the Home version. If I go to the control panel System and click on advanced settings then click on the Computer Name tab then the Network ID button the button for business network is darkened. I have tried changing it but after I do and restart it is still on the business one. If I go past the business one it askes if I'm on a Domain or not and the domain is darkened. I have tried checking the my company uses a network without a domain but again it comes back with the domain darkened. It cerationly acts like it's a workstation with no domain since I log on normally although I have to press ctl,alt, delete to get a logon. Further thoughts?

Ok, IP config looks good. this is what I would recommend... If this works, the issue is either something funky with the DSL router providing DNS Proxy services, or the NIC drivers. (You should make sure you have the most up to date NIC drivers in any case-check with the NIC vendor) On your WIN 7 computer, you can leave it as a DHCP client gettings its IP, subnet mask, and gateway info from the router. However, for the client DNS settings, change it to your ISPs (4.2.2.2). You can do this by accessing your NIC's properties... click on start, run, type ncpa.cpl. Then access the properties of the NIC, IPv4 properties, general tab. type in 4.2.2.2 for the client DNS settings. Create a Shortcut for Your Network Connections http://www.anitkb.com/2010/10/create-shortcut-for-your-network.html Run in this config for a while, if all goes well and you do not loose DNS function...well then its either the NIC drivers or your router. I would think the problem is with the router since this happens when you bring the printer on line. Maybe there is something wrong with the dNS proxy services running on the router...just a thought. Make sure the router is up to date on firmware. Visit: anITKB.com, an IT Knowledge Base.

Thanks for the suggestions. I have tried setting the network DNS to various locations and that made no difference. I checked with Nvidia (the network card is part of the motherboard chipset, which is theirs) and found that there was a recent update for the driver. I downloaded it and then discovered that I had installed it a few days ago as part of a regular windows update. I decided to install it again, just in case something had gone wrong. It has been running for around 15 minutes now and the DNS still works. If it continues (I have to quit now) then it will be a network driver problem. Let's hope! I am still wondering what the printer has to do with it. Also I still can't change from a business network to a home network. I'm wondering why.

Unfortunatly, after around half hour last night I again lost the DNS! I think that I am on to something though. When the DNS is working and I do command "nslookup msn.com", I get the msn.com address. If I just type nslookup with no address, I get "UnKnown can"t find nslookup: Non-existent domain". After time passes and I lose the ability to get new addresses (lost DNS), the action of nslookup changes. Just typing nslookup now return a > and typing help return a big list of commands for nslookup. I suspect that the machine has changed from a workstation to a machine running in a domain but I don't know enough about this to be sure. Looking at the C309 printer page, there is a section on mDNS that provides a domain name and a service name but there is no provision for turning it on or off. It looks to me like some action on the part of the printer is convincing my win7 pro desktop that it is now part of a domain! It's the weekend, don't know if anyone is watching this, I'll try to check it occasionally. Would sure appreciate advice as to how to get out of this annoying situation. I suspect from reading google hits that there are other in a similar situation. Bud

Hello Bud, You dont have to worry about the domain/workgroup concern. Either a computer is a member of a domain or a workgroup. Its not going to change on its own. Regardless, domain membership will have no effect on DNS name resolution. With regard to "After time passes and I lose the ability to get new addresses (lost DNS), the action of nslookup changes. ", when this happens, does your computer still have network connectivity? Can you PING another host or the gateway? Can you ping past the gateway? When pinging do not use host names, just ping by IP. This will help us determine if the problem is a general TCP/IP problem or a DNS client problem. By the way, make sure the Win 7 computer has the latest network drivers installed (visit the vendor's website for the download, not from Windows UPdate). Visit: anITKB.com, an IT Knowledge Base.

Regarding loss of DNS, the computer still has conectivity to the internet. I can ping IP's by numeric address, not by name. I can ping my IP's DNS servers (72.235.80.12/4) but nslookup will not retrive anything from them. To repeat, there is no loss of network connectivity. I can also change DNS clients and the same things happen. For a client I can use the router (192.168.200.1), the ISP's or another, for example 156.154.70.22. The same things happen when I turn on the printer. As I mentioned before, I have the latest network driver, obtained both from windows update and reinstalled from Nvidia's website. And, I'm still wondering why I cannot change the computer from a business network to a home one. Is it possible that the computer is looking for a DNS server that is part of the domain? Bud

With regard to your question about the membership, if you are logging In with a an account that has admin credentials, you should be able to union it from the domain. The workgroup and domain membership is not going to affect the dns client. I can't think of any reason why the printer would impact this computer's dns client. There is no reason. If there is a femporary bug, uninstalling the NIC from device manager and reinstalling may fix it. At this point, it definitely not an ip conflict. I had previously thought it could have been a MAC conflict which could cause a similar event. I would try the reinstall of the NIC or add another NiC to test and further scope the problem. This is going to be one of those off the wall, nutty issues.Visit: anITKB.com, an IT Knowledge Base.

Regarding the network card, it occurred to me that I have Ubuntu Linux on the desktop as a dual boot. I'm now running Ubuntu with Firefox and with the C309 printer online. I have printed a page, tried various web addresses and have not lost DNS ability. I'm using the same NIC (different driver of course) and the same router. The router has given me the same address (same network card0. I'm going to switch back to Win7 pro and try a few other things. Will report later. Bud

Hello Bud, I feel pretty confident that the issue is with the Win 7 box. Again, when you exhaust all troubleshooting, try uninstalling the NIC and reinstalling using Device Manager. I have seen over the years that this is a last resort when all else fails. Visit: anITKB.com, an IT Knowledge Base.

I did the last resort, uninstalled the Network drivers and rebooted. This also removed or changed the display drivers, they are all Nivida. Got them all back finally and also got back the loss of DNS. It seems to be something in the 7 pro is blocking access to DNS. When it's lost, nslookup reports no response from server. I can change the DNS address, and when I query with nslookup it reports the new address and still says no response. Meanwhile Laptop has no problem with DNS. I have gone through the software that HP provides since there seems to be a connection in that when one of the printers comes on-line, I lose the DNS. Using the HP Network Diagnostic Utility, I can stop "Installed HP Services" and that seems to cure the problem. These services are not all listed as services in the Computer Management window. I will verify that the problem is truely stopped and then try to find out which "service" is the one that does it. Hopefull the next report I make will be the last!

Wow, this definately has been a difficult issue to resolve. It sounds like you are getting close.Visit: anITKB.com, an IT Knowledge Base.

Looks like I found it, except I'm not sure what it is. By shutting off the "Installed HP Services" on the HP Network Diagnostic Utility, it's been 24 hours with no loss of DNA. The services listed are 1) SLP, 2) Context Manager, 3) Device Discovery. Turning them on an off indivitually shows that the SLP one is the guilty party. On the Win7 Services list, it's HP Network Devices Support, I've disabled it. The only problem that has shown up is a little difficulty in using the Scan feature on the C309, the list of activities does not come up without clicking on Home first. Right now, for me, the problem is solved but it obviously isn"t. There is a lot of information on SLP at https://h20392.www2.hp.com/portal/swdepot/displayProductInfo.do?productNumber=HPUXSLP. After reading it, I would guess that this application is a subset of SLP. My question is why would this service block DNS on Win 7 PRO only? I have the same software on Laptop (Win7 Home Premium), the service is running and no DNS problems. When this problem starts, it looks like a loss of internet connectivity. IE8 will offer to troubleshoot and then tells you to restart your modem. There must be other people who have this problem and haven't found a solution yet. Disabling a service to fix it doesn't seem right. Maybe someone else knows the answer? Bud

You may want to check on the HP Forums and/or report it to them for further analysis. It may not be a widespread problem.Visit: anITKB.com, an IT Knowledge Base.