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dgrrrFlag for United States of America

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When plugging in Ethernet loses Wireless internet

(I know this is a common question, but I can't find it, not precisely.  I must be using poor search criteria).

Let's say XP connects to the internet using a wireless adapter, and you plug in an NIC / ethernet cable, which IS connected to a network, but is NOT connected the internet... ... and you lose internet connectivity.

(1) Is this normal for XP?

(2) Is it because XP must choose to use one or the other -- for BOTH internet AND networking?

(3) Does XP always choose ethernet over wireless (for internet/networking) -- or does it judge speeds and pick the fastest?

(4) Let's say the network is configured right for BOTH the wireless AND ethernet -- and I get the same behavior (plugging in one device impairs the other from connecting) -- what's the most likely cause?

(5) Are the same answers above (1-4) true for Windows 98?

thx!
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kiddanger
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Hi dgrrr,

You generally don't connect via a wireless NIC to the Internet.  You connect to an Access Point that connects to a router or has one builtin.
XP is not a server OS.  You need to use ICS so the wired NIC will have access to the Internet.
This should help: http://www.practicallynetworked.com/sharing/xp_ics/

-kid-
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ASKER

Not sure what you mean -- I think there's a misunderstanding.  First -- what's a "wireless NIC"?  And how is a "server os" or "ICS" related?

I think you may have misread part of my post -- it's  only about ONE OS (one PC), and how it chooses using it's wireless adapter versus using it's NIC adapter

(I'm assuming that NIC is synonymous with Ethernet...)
NIC = Network Interface Card

A "server OS" can communicate on both NICs at the same time.  ICS (Internet Connection Sharing) allows a desktop to be a router so you could have a dialup or broadband connection on a desktop and share that connection with other peer users.  Why else would you need a wireless connection and a wired connection at the same time?

Unless you route, the OS doesn't know which way you want to communicate.  You have a client OS, not a "server OS."  You may also be trying to use them on the same network and that's not going to happen.  Please fill in any part I am misunderstanding.
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ASKER

Don't the terms "client / server" refer to activities like FTP or VPN?  Here we're only talking about a PC communicating with a router...

LIke anyone who sets up a wireless router, I always used an XP pc -- and first I connect the router directly to the xp pc (with an ethernet/NIC card) and configure the router for wired internet access.  Then I configure the router's wireless settings.  Then my wireless adapter connects.  

Then, at that point, I can plug in or unplug my ethernet cable.  Doesn't matter.  Both connect.  The PC seems to be able to deal with either / both.


BUT - in the above case, where the ethernet cable goes to one router (which is NOT connected to the internet), and the wireless adapter connects to a DIFFERENT ROUTER which IS connected to the web -- whenever I plugged in the ethernet cable, I lost internet access. In other words, the comptuer seemed to default to using the ethernet card, even tho it wasn't reaching the web.

Hence my questions...
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ASKER

Sorry, I should clarify.  First, clearly, you can use other OS's besides XP to setup a router.

Second -- in my post just before this one (directly above this one), I refer to TWO DIFFERENT SITUATIONS --
(1) using XP to set up ONE wireless router that's connected to the web (a common situation)
(2) my ORIGINAL POST -- 2 routers (one wired without web, the other wireless with web) -- which generated the initial questions.


In the post directly above/before this one, when I said, "BUT - in the above case...", I should have said, "In the case presented in my ORIGINAL POST at the TOP OF THE PAGE)

(wish we could EDIT these posts!)
I agree, editing would be great.

When you connect wired and wireless, one at a time, yes it works because there is only one interface showing connected.  When you try to connect both at the same time to two different routes, no, only the latter will connect.  When it is removed, the first one will be able to communicate again.

The term client/server means server role and client role.  A client is a workstation.  All Windows OS can run in server and client mode, depending on the task.  If you share your drive on a workstation, it is the same as sharing on a server.  That is a server role.

The term client/server is in lieu having a terminal or a PC terminal connected to a host as in a mainframe with terminals that only send keyboard input and receive video responses.  In a client/server environment, apps usually run on the client and data is stored on the server.  This allows the client to use it's processor to process data; the server just provides [servers] the data to be processed.  In a host environment, all processing is performed on the host, thus just video responses are returned to the terminal.  It works the same with terminal services and remote desktop.
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ASKER

I see. Thanks for explaining both things.

Only remaining question is #3 -- but in a normal situation -- when a wireless router is configured correctly for network and internet, and my XP pc sees it fine, via both adapters (wireless and ethernet)...

... (so both adapters are seeing the same router correctly)...

-- How does XP decide which one to use? (does it judge speed, or have a preferred protocol?)


thx!
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glebn

Open a command prompt and type "route print".

The resulting information is used by Windows to route traffic. If there are two identical Network Destinations then the one with the lower metric is used. Note also it uses routes from specific to general so the route to 10.10.1.0 would be used before the route to 0.0.0.0.

By the way, I didn't have a chance to read the history above in detail, but did you have your question answered? One common problem I see which causes the behavior you describe is when users enter a default gateway when none exists (e.g. there is no router at the default gateway address). For example, you say your NIC is connected to your LAN but your LAN isn't connected to the Internet. If your LAN is flat (i.e. 1 subnet with no routing) then your NIC should NOT have a default gateway. If you enter one then when you connect an ethernet cable you will lose Internet because your computer will try to send Internet traffic to the gateway you setup for your ethernet NIC because it almost certainly has a lower metric than your wireless NIC.

Lastly, if you LAN is not flat (i.e. there are multiple subnets) and it is not connected to the Internet, then you should delete the default route for your NIC and enter a manual one for all the subnets on your LAN.
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kiddanger
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to kiddanger - I hope you're not mad that I split the points between you and glebn, although you were first to respond.  I think I was better able to understand his answers because they were geared to my newbie level of knowledge.  I see that you did mention, early on, the multiple router issue, which I think is equivalent to the subnet issue -- "When you try to connect both at the same time to two different routes".


to both:
I'm looking for a newbie networking glossary, that's easy enough for me to understand, but that's contains terms like "metric".  (can't find the meaning in this context)

Ironically, when I google "define:nic", some of the results equate it with ethernet, others with a cabled (wired) network connection. But the majority don't specify, or allow for wireless too, and these definitions sound more professional.  But I've seen "NIC card" and "ethernet card" used interchangeably so often that I wonder how many other people (besides me) make this mistake...


thx!
I've seen a lot of explanations of the core concepts of TCP/IP, but my favorite is actually in a Windows server book called "Mastering Windows 2000 Server" by Mark Minasi. The TCP/IP discussion is worth the price of the book. Note that there is an updated one for Windows 2003 Server, but I'm sure it still contains the TCP/IP discussion. Manasi explains all the key concepts of TCP/IP networking in a very understandable way but in depth enough that you'll be able to think through most networking problems in a systematic way.

Sorry, don't have a good glossary, but try Googling on words like "nic ethernet subnet gateway glossary".
NIC = Network Interface Card - it can be wired or wireless
http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GGLG,GGLG:2006-09,GGLG:en&q=wireless+nic

Ethernet is a CSMA/CD topology
For beginners:
http://computer.howstuffworks.com/ethernet.htm
Beyond beginners:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/ethernet.htm

TCP/IP is a suite of protocols
http://www.webopedia.com/TERM/T/TCP_IP.html
http://www.cisco.com/warp/public/535/4.html
http://www.historyoftheinternet.com/chap4.html

Ethernet is not a NIC, but there are Ethernet NICs, as well as Token Ring, ArcNet, TCNS, FDDI (DAS and SAS), CDDI, etc.  An Ethernet NIC can have the following connectors, DIX (15 pin female), BNC (coax), RJ-45
http://www.kmj.com/nic.html