Lose Internet Connection Periodically

Point value changed by question poster.

Do you have any bridges on your lan connections if so try removing them.

Also check with your modem and router's manufacturer to see if this is a known issues they may have a firmware upgrade that will fix the problem.

I would venture it's your router that is causing the dropped connection. As to why, could be a # of issues. WAG, it is a firmware bug.

I had a SMC 7004 ABR router a couple of years back. Dumped it as it seemed to just be flakey. Went with a Linksys.

I agree with the other posters that a router problem is the most likely. When you say a reboot fixes it, is that a reboot of the router? I too have seen somewhat "flakey" versions of this product. Current firmware is version 1.93 and is available for download from www.smc.com. You can check yours by logging in to the router, on the 'tools' page there is "Information" which should list the current version number. HTH,

---Will

Can I assume that when YOU cannot browse the internet, the same goes for the other PCs on the network? When this happens can you ping an IP address outside of the network (ie your ISP?). Could it be a problem with the IP address of your DNS server (is it set to detect automatically or do you specify one or more DNS IP addresses)? Depending on your ability to ping outside the network when your brower "goes down" you may want to try a different DNS server. If you and the rest of the LAN cannot ping out, then it sounds like either your router is flakey or your ISP is flakey.

A reboot of what? The switch? The modem/router?
You don't mention what type of connection you have, xDSL? Cable? T-1?
I have seen this happen when using xDSL, that uses PPPoA (PPP over ATM, not to be confused with PPPoE), or EoA (Ethernet over ATM). I don't know if a T-1 that uses any of the above (PPPoA, or EoA) has the same problem. I don't know exactly what the problem is, but every so often the PPP will get corrupted and the only option is a reboot of the PPP client device. But I'm not sure why it happens on EoA.
In most case if this is the problem you only have 2 options:
1. Work with your ISP to correct this, make them aware of this problem, and see if they are interested in fixing it. If not you will be forced to use option 2
2. Change ISP.
However I did see that sometimes in the case of xDSL changing the Modem/Router to another brand helped (BestTel looks to be the best).

If you can ping computers on the internet, but cannot surf the web or get email, then your problem is the DNS. If you are getting the DNS servers from you ISP, try to entering them manually in the TCP/IP options menue. If that doesn't work, try to use someone elses DNS servers.

You can check if it DNS by typing "nslookup www.google.com" or some other site. If you get "... can't find server: Non-exixtent domain", then type in "nslookup" and enter. At the > prompt, type "server 205.152.0.5" and enter (this will make bellsouth's name server as the active name server or use any DNS server you may know about). Then type in "www.google.com" and enter. If you get an IP address, then you know your problem is the DNS server. Please make sure you enter the commands above without the ".

Hope this helps.

1 system has gigabit ethernet, the others 100Mbps.
Disabling the antivirus and firewall does not help.
Both ping and nslookup work fine.
tracert never works, but it gets as far as it always does (can't make it past their 1st router).

Point value changed by question poster.

Windows 95b (I have a multiboot system that can go into several systems) seems unaffected by the problem, while all of my Windows 2000 machines are affected.

my question to you is how many pc's are connected to your router and you say you have a switch so you must have quite a few computers connected have you tried checking the event viewer it is a tool for troubleshooting also have you installed performance monitor you can use it for a varitey of reasons.
hope this helps

Here is what I gather the facts are:
1. Win2k machines
2. Win9x machines don't have this problem (although I don't know how you tested this since it happens randomly, it could just be that the 9x machine wasn't in the mood of making trouble).
3. When you reboot the OS (win2k) that machine doesn't have the problem anymore.
4. The router doesn't have to be rebooted for the computers to clean up the problem, just the computers have to be rebooted.
5. The modem is not the problem, also because a reboot from just the computer will help, without rebooting the router/switch/modem.
Here is the troubleshooting technique you should use:
Can you use the network locally?
If not then maybe the switch is the problem. You will ask then why don't you have to restart the switch? The answer to this is; if the switch is making trouble it can just corrupt the ARP table for the clients but the switch works fine, when you reboot the client the ARP table gets rebuild. How can you verify this? at a command prompt type:
arp -a
if anything is listed then type:
arp -d *
now test it, if the problem is gone then the problem is an ARP problem, which in most cases means that something is wrong with the Switch. The fact that ICMP (PING) works is no surprise to me, since I've seen before that a ping will work even with a corrupted ARP table.
Continued....

I have a wireless network at home that used to periodically lose all connectivety to the internet but it still seemed to be all connected up. I found a few things:

1) that your wireless security settings may be affecting the connection. You may also want to check that you don't accidentaly have another wireless profile set up that is overriding the connection.

2) Now I know that it also happens when you connect directly, I found that I had a wireless connector that was crapping out and seemed to take the whole thing offline after a while - had to reset the box.
-Is there one specific machine that seems to go out on your network first all the time?

3) You may also want to try reseting the box and changing the name and specifics to the connection.

4) Does re-making a connection ever link everything back up

Logging out and logging back in makes it so browsing and reading email are again possible.

The problem isn't with you but your ISP's routers. Take a look at this article by Microsoft. What you are describing are "black holes" being caused by small mtu settings on routers between you and the real world.

Look at this article and then perform an expanded search based upon the issues it mentions:

http://support.microsoft.com/default.aspx?scid=kb;EN-US;314825

Since you say that logging off and then on fixes the problem. I think the problem might be a spyware or adware that is creating this problem. Since in most case these programs only run in the logged on user context, when you log off these programs are terminated. Download spy bot search & destroy, Ad-Aware and the like and scan you computer. Also scan your computer against viruses. You can use housecall.antivirus.com to scan your computer for free.

I experience the same exact problem - direct connection to cable modem (no router). Windows 98se. I'm convinced it is a registry problem caused by spyware/virus.

My experience is not extensive enough to attempt to fix the registry manually.

I continue to experience the problem as described and strive to fix the registry with some methods.

I'de have to agree with the one whom previously said the arp cache was bad, however you said you checked that. The only other option for you at this point is check fourms for that product for this problem being your switch. I had the same problem with my linksys, so I went to there website and "flashed" the product. Try that with SMC and maybe try another switch/router combo.

Telecoms do not provide static ip`s for customers using broadband connections (PPPoA)over ATM networks.Ips` are assigned dynamically.
As a telecom insider,I know that the situation you mention is very prevalent.I would venture to say: If broadband (DSL,Cable etc.) connections were stable and drop free, they would be a very economical alternative to leased lines w/static IPs. I have DSL 768 using a 2Wire modem. Before this I had constant problems just like the ones you are having.With this unit,I am able to perform varied diagnostics.I wind up doing a re-sync which of course leaves me with a different IP.I have Win 98, Win 2000 pro and XP pro boxes and all are affected..............
I have found that all the problems are ISP/ATM related (gremlins);it would seem that this makes setting up and maintaining cheap VPN`s too much of a hassle and not an alternative to static ip leased internet lines.

Attempt to connect directly to your broadband connection
without the router, switch, firewalls, or antivirus... nothing but
an ethernet connection to your broadband modem.

If it works, then slowly add things, one by one. First the router,
then the switch, then the firewalls - one by one, then the
antivirus application. When it stops working after one of them,
you'll know which is causing the problem - if it's a problem with
one of them.

If several computers are experiencing the problem, perhaps it's
an issue at your ISP. Have you contacted them?

You might also try a friend's Mac, Linux, or Win95 machine.
Perhaps it's a problem with your specific SP of 2000, or maybe
one of Microsoft's little "security fixes."

This is not an answer, but a comment: I have the SAME EXACT problem, and I'm so glad that I have found someone else with it! :) My specs are slightly different however, which makes me believe that it is probably a problem with the OS and most likely a security patch that microsoft has released lately...? (Or worse, maybe a fluky conflict with one of our drivers and a patch).

I am using XP Pro SP2, and have updated my PC with all available security patches from Microsoft (possible problem).

I took my router out of the equation and have my PC connected directly to my Cable Modem. My ISP is Time Warner Cable (in California) -- and have had them visit 3 times (all is good from their end they continually claim). I am on my 3rd network card (and have ruled out that it is a network card problem.) I lose internet connection after about 30 minutes (althought it varies) and must reboot my PC (not cable modem) to fix this problem. When I lose the connection, I still have an ip address from my ISP on my PC. I can renew and release this IP address with no problem (with browsing capabilities gone) but do not regain browsing capabilities. Have tried multiple browsers.

I'm testing with another computer now, to see if I have the same problem with another XP Pro computer. All signs have been good so far (so it appears like it might be my 1 PC -- I'll give an update.) I have made sure my PC is clean (with NAV Pro 2003 and Ad-Aware Spyware Cleaning Software.) I have no firewall software or hardware running...

I don't mean to add confusion to original post, but it seems like we have the same problem. It also seems like it's a fairly unique problem (as I haven't had much luck finding any other info on it.) At the least: Any thoughts on where we could find more info on a problem like this?

Thanks very much!

Change your provider!

Sounds like spyware to me. You might want to check the lavasoft website and download the VX2Finder. http://www.lavasoft.nu/software/plugins/vx2cleaner.shtml
This spyware locks up some (not all) TCP/IP after running on your system for a given time period. Haven't figured this one out yet but vx2 resolved this for me.

Best Regards,

Troy

I had the same problem with my DSL modem. I spent weeks trying to figure it out. They sent tech. out but could find nothing wrong. They replaced my modem twice. Turned out that it was a bad modem.

I don't know if you have checked this but, when you loose connectivity, have you checked you're IP address (IPconfig /all). The reason I ask is that you are running a sygate firewall and it may be a conflict between that firewall and something within the router. My initial thought was that you had NAT/Firewall enabled on the router and that was causing the problem. It may also be of some help to put 2 different DNS server addresses in the SMC as this may eliminate the possibility of this being the problem. Also check that the firewall on the barricade is not enabled, as it appears that although you can still ping, it is the high end stuff that's causing issues.

if you suspect your router and i would, put it on a ups. put it on a battery for a while and see if that affects things. also comb thru configuration see if you have a 'ppp autoconnect' option. if you do, enable it. call you isp about this and ask if they have more reliable router. just see what they say you don't have to do anything.
my intermittant disconnects were something the boss picked on me about for weeks. we fixed ours by resetting the router not rebooting so maybe not your issue. anyhow, after weeks of asking around, nobody gave me any usefull information except finally phone company dsl router guys. try to get 2nd level support there even if didn't buy router from them. they suggested autoconnect and battery and autoconnect helped some and battery finally fixed it. it is always fixable. bull crap notwithstanding

You may want to give this a try.

Try going into your properties page of your network adapter and setting all your machines to connect at the same speed. Try having all the computers connect at 10mbps/half duplex. It may be that your ISP cannot autodetect your connection speed. I have run into this a couple of times on my network where a machine will run fine and connect most of the time but on occasion the auto detect does not negotiate properly. When this happens I am able to ping the server but cannot authenticate to it. Changing the network card to 10mbps/half duplex fixes the problem without a restart. Just something to try with your fingers crossed. :)

Hope this turns out to be to be helpful.

I saw a similar issue once, no matter what was hooked up (PC or Linksys router) it would "freeze" up at seemingly random times.

I put a SonicWALL spare I had in there, and when Internet access went down I found I was able to still log into it - and the logs reported a massive DDOS attack against the network. It turned out the little Linksys wasn't able to handle the malformed packetstorm and just froze up, as did any PC plugged into it.

In the end the client bought a SonicWALL and I set it up in stealth mode (any probe to it would timeout).

They still had a loss of Internet when the attack came in but when it was done Internet came back without a reboot. After a few weeks (since it was in Stealth) the attacker gave up, probably thinking they changed their WAN IP address.

Zaf

Not so much an answer as a thought:

During the problem you can ping through,
have you ever checked Ping Timings and TraceRt
to known Internet IP's to see if your ISP
is rerouting you through an alternate server or setting?

Just curious if timings and routing are same
during good time vs bad time.

If you've changed the modem, changed the connection (PC and router), changed the Ethernet cable and no significant activity preceeds a failure - then only two things come to mind:

1. Environment - maybe plug the modem/router/PC into a small UPS. Also double check that your Ethernet cabling doesn't run across any large power sources.

2. Upstream problem - if there are two connections, and you've thoroughly troubleshot one side... maybe the problem lies in the connection they have you plugged into somewhere between your junction box and their modems on the other side. While it may be difficult for an ISP who "doesn't care" to check their own equipment - if you've eliminated everything else as Holmes would say: "the only remaining conclusion - however improbable, must be correct"

If this happens when you're directly connecting and with
multiple computers, then I'm beginning to wonder if it's not an
incorrectible problem for you and instead a major problem at
your Broadband ISP.

Try complaining to the Better Business Bureau (http://
www.bbb.org) about the problems and explain that they've been
very unhelpful and that you've tried to correct it and failed. Since
it happens when you're direct connected, you don't need to
mention your routers or other equipment - they'll probably just
say they're unsupported.

I've found the BBB to be very helpful with unhelpful companies.

fascinating. i do not have time to read thoroughly. just 2 cents worth.
so you say when this happens, resetting the router does not bring you back. weird
so you say when this happens, booting into win95b does bring you back.
if rebooting win2k brings you back then wonder if you set static ip address on box for test would problem go away...
how do you get back when this happens. do you just have to wait? or do you reboot to get back
sure sounds like os vs wireless problem.
do you have latest greatest updates on your wireless access point? can you try another (brand) of wireless access point?]
when you go down on win2k box, can you bring it back with ipcconfig /release then /renew?
when it goes down can you ping your isp's dns servers?
i think router is funky and due to changes in your phone companys switch programming router is losing dns maybe and not getting it back. see if router can be updated. call your phone company and ask for broadband router suppport.

To test and troubleshoot faulty connections go to

http://www.dslreports.com/tools

To eliminate possible problems from files on your system do the following steps.

Run Explorer.exe make sure hidden and system files can be viewed.

From the tools menu select folder options, then view then put a check next to:

Display contents of system folders
Show hidden files and folders.

Remove the check from:
Hide extensions of known types
Hide protected operating system files.

Select yes when prompted.

Now from the left pane, navigate to C:\Documents and Settings\YourUsername Folder.

Open the Cookies folder and delete all.

While still in the Documents and Settings folder Open:
Local Settings\Temp\ delete all tmp files. Then highlight, cut and paste everything else to a new location. Don't delete because these are your uninstall files and folders.

Local Settings\Temporary Internet Files\Content.IE5 and delete everything including then delete the Content.IE5 folder.

From device manager uninstall the network and Dialup Adapters.

Don't reboot yet!

From add remove programs uninstall all networking features.

Have you tried changing the location of your modem? If the modem is placed to close to the monitor it can cause interference. Going out on a limb.

Hey, I have the same problem with almost the same setup. I have 3 PC's connected to a linksys router. 2 are hardwired Windows2000 machines and 1 is a wireless WindowsXP laptop. What I see is as long as the PC's are on and remain IDLE for X period of length, they lose all internet capability. I haven't even begun to investigate the problem, but my fix is to reboot the modem only. All PC's are affected and cannot connect. The really only thing I notice is, if one of the Win2k machines are on indefinitely, everything is okay, but once my wireless laptop sits too long, everything gets hosed....Sorry I've given nothing to help the cause, but I will start to look at the next time it happens and post back if I can find anything....

Reference Answer 25:

I was hoping to see during a direct connection
to the provider when entered the query. Sorry
I didn't word well.

You have changed the status to answered, what was
the final solution you adopted? (You rejected all
answers from what I see)

Anyway, I had to deal with an ISP who had some
very interesting settings in his Broadband setup.
The first set in the solution was to determine
which of his servers was causing the problem.
The Ping and Tracert together helped identify
a problem on their end. Of course, they will never
admit it, however, by the end of the testing
a report sent to my ISP resulted in a magical fix
about 3 days later.

Best of Luck,
CharlieP

Here's what I think may be your problem.

The "DNS Client" which caches both positive and negative connects may be the problem. Not the Temporary Internet Cache but DNS. If your ISP is too congested or overloaded it may take too long to respond to your request at times and the negative DNS is then recorded. After that until the cache expires it would stop the connection untill the cache is cleared. More attempts to make the connection will only lengthen the time it would take for the problem to stop.

The DNS address would be one of the 2 provided by your ISP. Try switching them around, make the primary the secondary and see if there's a difference. With some ISP's this may not work.

Rebooting or logging off and back on stops the problem since the DNS cache is cleared.

You can disable the negative part of the DNS caching with a registry edit.

Remember to back up the registry before making changes.

Navigate to the following:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters]

Highlight the Parameters folder then move over to the right pane and right click. Select "NEW" and choose "DWORD" add each of the 3 keys listed below. Note all three should be set to a value of zero.

NegativeCacheTime
NetFailureCacheTime
NegativeSOACacheTime

To go back to your original settings restore the backup of the registry.

Even though it doesn't seem to be a problem with the router you can update the firmware. Here is the site to do that at.

http://tinyurl.com/6899o

Good luck.

I recently had to upgrade my Internet Explorers because a website I use alot made a change that seems to interfere with 5.5. I have not had the problem since. I am leaving the question open for now and if the problem rears its head again I will try the options I have not yet responded to.

>Unfortunately I have complained to the Better Business Bureau
>before about companies and have seen no results. Customer
>Service definately seems to be at a low point these days.

If any of several different computers are plugged in without the
router or any switches or firewall software, then I don't think the
problem would be fixable for you.

There's no way to tell whether the BBB can solve your complaint
without trying, and that seems to be the only thing left to do. It
works for some companies and others don't care... I've found
that ISPs usually od care.

My unplanned upgrade of Internet Explorer must have changed whatever system component was causing the problem. Systems where I have upgraded no longer exhibit the problem behavior. Very surprising.

This question was closed by the author