Office network is killing my routers!

Hope you can help me out.

I had this scenario..
Internet -> ISP router (WIFI enable) -> switches -> computers

After a while, the router will stop responding and the only way to bring back the network was resetting the router to Factory default and configuring it again…
The problem will happen every week, sometimes every three days, and sometimes every month.

So I changed the router from the ISP to another one of the same Brand and same model.... and.... the same problem… the router stopped responding…

I changed ISP to fiber optic and my scenario was the same
Internet -> ISP router (WIFI enable) -> switches -> computers

Now I have a Dlink DIR-600, and I thought that the problem was solved… but NOOO... again, my new router stopped working… sometimes after a week, sometimes after an hour.....

What possible problems could cause this?... I am checking for virus on the entire computers for now…

Can someone help me?
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Where is the router located?

I've had similar problems where a small router is sitting on top of a switch or a firewall and overheating. Mountable switches usually have fans at the sides or back and emit quite hot air. Are you finding that the router feels hot at all?

Another possiblilty is you've got some sort of broadcast storm happening which is affecting your router. Are there any problems with speed on the network in general when this problem occurs. You could try a packet analyser like Wireshark to see if there's anything unusual going on.
Have you only used D-Link? I've had this problem with all D-link routers, specifically with the wireless.

But a simple power cycle fixes it, but your saying you have to factory reset the thing? That's odd.

What's the load on the office? Don't use these cheap off the shelf ones from walmart for a larger office. It can't keep up with the load possibly..just like a processor with to much load on a normal desktop computer.

Again if it's a larger network, check for spanning tree loops and network congestion. Use wireshark and see if there's a lot of noise on the network. That could cause these problems.

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marpanetAuthor Commented:
The router is Wall mounted....

Before I did not have a Dlink, it was another Brand used by the other ISP, now I have a Dlink DIR-600 which only with a power cycle fixes the problem… the problem is that I cannot be doing the power cycle every day....

Let me do the wireshark analysis to check for a problem....

I just connected the router and the two switches to the same power supply, a UPS...

We only have 10 computers.... and like 3 WIFI computers… and do not have any slowdowns..
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Honestly this device is a very basic SOHO and is design for a limited number of devices. Also if you have the DIR-600 and not the 601 bad news
Its was end of life in 12/09.

Even if a power cycle fixes your issues I would rule out any temperature concerns, I would lean more towards a DOS attack / Flood or if you are maxing out the firewalls proc/memory at which point will cause any router to stop processing requests and lock up. I would see if the management page has a resource meter that tells you what the utilization is at but, I kind of doubt this device has one.

If you upgraded to a entry level business platform firewall ie a Sonicwall TZ series, a Watchguard or even a Juniper SSG5, I woudl be confident that this would solve your issue and these devices do give you your utilization on your resources and can help you identifya DOS/Flood attack.
marpanetAuthor Commented:
Buying a new router might solve the problem??.... I do have an Exchange server which communicates to some devices outside our company..... but then again.... only to 10 devices at max..... if this issue happens again I will have a more profesional router…

Does changing my old switches will help?
Well I think it's more so the brand of router too.... I might be crazy, but again every time I bought a D-Link for home I have to freaking power cycle mine everyday just like in your case. So I figured hey..I'll buy a more expensive router. So I got the D-Link Dir-655...and guess what? Still have to power cycle it.

I switched back to my old Netgear and and also tried my linksys, I have absolutely no problem with them at all.
If your Wireshark capture doesn't show any indications of a denial of service attack /flood present on your network I would highly recommend the replacement of your firewall. Also be sure to run your packet capture at the time your router stops working to be sure to rule this out.

 Also my point on a more business platform device is you get more visibility in to whats is happening with the device when there is an issue.
I can't say I have ever had a good experience with a D-Link product in a business environment.

To answer your second part of the question, no changing out your switches will not have an effect on this issue and in a small office with 10+/- PCs small work-group switches are normally fine. As long as they are switches and not hubs.
marpanetAuthor Commented:
I changed one of my switches..... it was very old, almost a hub hehehe
As I was changing it, I noticed that two ports of this switch where making a flickering pattern not consistent, and also two ports where blinking even without an Ethernet cable connected, so, for sure the switch is faulty, not saying this will solve my issue, but for starter I changed this switch for a new one.... will try it out and make the other tests given..

Waiting for my network to burst into flames until my next post! heheh
Best regards,
Well if the switch has a flapping port it could be what is locking up your firewall. A flapping port will create a flood of traffic bombarding your firewalls LAN port.
It's definetly worth swapping it out and waiting to see what happens.
request you to check your network broadcasting.
generally it happens in port 137/138/445
marpanetAuthor Commented:
Guess what...… bursted into flames yesterday at night...… even with the new switch, the router passed out........... I am trying to run wireshark but in my Windows 8 consumer preview won´t work… I will install it on another computer running xp....

Another thing… I have an old computer running Windows xp, this computer is only used for the scanner, yesterday, I did an antivirus check and the screen didn´t work at all, I manage to remove some viruses from my computer through the network, and the screen worked again… I thought that the actual antivirus was compromised to I changed to another antivirus and found another virus.... so, I will do a complete virus check, maybe this computer that has been sitting there alone for a while is the one giving me all the headaches....

Is sing the Wireshark easy?..

Diprajbasu, how do I check my network broadcasting?
Wireshark will allow you to pick an interface you want to begin a packet capture on and then start the capture.
If you do have a virus infected machine loading up your network it will not be hard to miss, you can sort by source IP and will be able to see the traffic that is being generated from that IP.
If you have issues running Wireshark if possible see if you can simply unplug that machine from the network over night and see if your problem still exists.
Strange problem impacting different routers. Since you seem to have more than one router on hand, try using both the ISP router and the D-link router, but break up the functionality. Use one for routing only and the other as AP only. This alone might help the situation if it's overloaded resources that's causing the corruptions. When something goes wrong, you'll have  some clue as to which part of the functionality is causing a problem and/or which device. You can then switch places for the devices and see if the same functionality fails or the same device fails.
Using Wireshark to analyse packets takes a little getting used to, but is easy enough to install. My advise would be to search the net for easy to use guide.

You can use Wireshark to check for broadcasts. The machine that you are installing it on will pick up packets destined to it's own ip but also broadcasted packets which will be sent to ip ending .255. If you find that one computer is sending out all of these broadcasts then there may be a virus causing it.

Are any of your computers experiencing network problems. It's possible that you may have a faulty NIC which is causing noise on the network.

I have to say though I haven't come across what you are experiencing. It's very strange.

Is it possible there may be a power surge problem?
marpanetAuthor Commented:
I connected both switches to an UPS, so I don´t think it´s a power supply problem…
I disconnected the computer that had virus and still the problem persist…. I will try out the wireshark on the next because today I am going away for vacations….. for now, because the router fails every day, I will plug on the secondary Internet unto my office, but next week I will do the wireshark test and try it out.

Best regards,
marpanet if that computer has viruses, unplug that thing from the network as not to affect other computers. Then run your anti-virus scans. Since it doesn't look like you have a corporate anti-virus I would make sure to put something like Windows Security Essentials on all the computers. It's free for business use, but only use if you have a small environment preferably. Just to initially get the viruses off malwarebytes is also a good free one, doesn't have a live scanner for the free version though.

Download wireshark here: Download

Use wireshark to see if there is a lot of noise, this is a easy guide on common commands Link

It's pretty self explanatory, you don't need to be a wizard by any means, just have to have a okay understanding of IP addressing and play with it for a little bit with the filters (otherwise you get a bunch of garbage)

And again it's my personal experience that D-Link routers are garbage being that I've had the SAME exact situation as you.
marpanetAuthor Commented:
Thank you, I promise I will install Wireshark tomorrow; the problem was that today I had two servers down from another office....

Yesterday, the people from my ISP came to check out the problem, for sure they didn´t know what was happening, so I changed to make another test...

Now, I took away the Dlink, and made my Windows 2003 the DHCP server, and the Internet Modem only do the Gateway function now.... for a while it worked good, I made the dlink an Access point and it failed, but only the wireless failed, so I changed the Dlink to an SMC Access point, and guess what?,, it failed too.... another thing happening was the suddenly I lost communication from my computer to my server (they are plugged in into the same switch), I took out the power on the switch and turned back on I once again I got back the communication..... That´s weird right????
marpanetAuthor Commented:
I installed Wireshark on one computer.... I got tons of lines which I think I know what they mean, my problema is that I do not know how to look for a flood attack or something that might be causing the problem..

Could you help me out? what do I have to look for?
"Now, I took away the Dlink, and made my Windows 2003 the DHCP server, and the Internet Modem only do the Gateway function now.... for a while it worked good, I made the dlink an Access point and it failed, but only the wireless failed, so I changed the Dlink to an SMC Access point, and guess what?,, it failed too.... another thing happening was the suddenly I lost communication from my computer to my server (they are plugged in into the same switch), I took out the power on the switch and turned back on I once again I got back the communication..... That´s weird right????"

Very strange. So you're getting failures in you switch and with AP separately? Does your server loose connection with ISP as well? There are multiple points of failure, which is very odd. Let's go back and double check that there truly are multiple failures, and not a common denominator.

When you say the AP's fail, do you know which part of the link failed? If it's the wired portion, are there any signs on the Ethernet line that show error (check the lights on both ends of the cable between the switch/router and the AP). Can you access the AP either via wireless or via a PC connected to the router? Us the configuration IP address when things are working and when things fail. The AP shouldn't fail at both ends. If the AP fails, it shouldn't bring down your router's other functions or your wired ISP connections.

Does unplugging and re-plugging the connections restore function? Rebooting an AP? How about a disconnected PC?
marpanetAuthor Commented:
The AP just failed again....
I was pinging from my computer to the AP, everything was fine, suddently lost connectiong, before unplugging the AP I unplugged the Ethernet cable and connected again, and there was NO asnwer, neither I could Access the configuration webpage....

Now because my server is the DHCP and the router only work as a gateway, the whole network stats online, only the wireless AP is falling appart…

Tomorrow I will be going for a 16 port switch to replace all of my switches.... but still I think the problema will persist.
Am I hearing that the rest of the hardwired network is intact, but the wireless AP is the only remaining problem? Does rebooting the AP fix it?

While ping from PC to AP (hardwired) goes dead, what do the wireless devices do? Do they still remain connected to the AP? Are the signal levels strong? How many APs have you tested? Wireless devices do fail as they age. How old are these devices?
marpanetAuthor Commented:
Guys!! I need your help..!! I think I solved the problem but do not know how to distribute the points awarded, I don´t want to make a bad decision in the point distribution…
This is what I think happened....
I know that the DIR-600 is horrible, the weird thing is that my SMC AP has always worked perfectly…..  Also all my old switches were too old, so I bought a 16 port gigabit switch so all devices are connected to the same switch (after replacing the switch the problem persisted).
So, what I did was bringing from home my AP (TpLink) I know this one is very cheap but it wasn’t fail in three days… Also I found in another laptop another virus…. So, with another virus taken out and my TPLINK AP everything is working fine until now.
I will take my SMC AP back to my home which I don´t think it will fail and leave the TPLINK in my office, so I think the solution was that maybe a potential virus in that laptop (using WIFI) was causing the AP to fail, and changing to a new AP.
Could you help me out?, Or should I decide for myself?
Best regards, and thank you every one of you for helping me out.
marpanetAuthor Commented:
I try to distribute the points..... I want to thank everyone that helped me out solving this issue.....

I cleaned all computer for viruses and changed the D-link Dir-600, I used the ISP only as a the Gateway and my Windows 2003 is now the DHCP server, I bough a better AP from another brand and until now everything is working fine, also I changed the switch (this didn´t fix my problema but my network is faster).

Thank you guys!!!!!!!!
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