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Oh, well that makes sense

December 31, 2009

Our Internet connection has never been great, but recently it degraded to awful.  Once a connection to a website was made, it was quite fast but making the connection was a frustrating process.  Turned out to be a NAT conflict between the modem and the router.  Once we got the modem to quit tryin’ to be mister DHCP an’ all that, and let the router do the DHCP and firewallin’ ‘n stuff, it’s a LOT faster.  The modem is in “bridge mode” now, which means it’s just a bridge between Verizon and the router.  What I don’t understand is why it got so bad recently but it’s working great now.

Over break this has cost me several days on projects.  Now to try and make up for lost time.

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  1. December 31, 2009 at 22:02 | #1

    It may be that DNS servers changed, and the IP clients had the old DNS info.  Is the modem really a router with modem built in?  That would explain why it wasn’t in bridge mode to start.

  2. December 31, 2009 at 22:19 | #2

    Yeah, maybe Verizon changed something that put them at odds to each other.  They had been working not too bad before, then last month it just all went to crap.

    The modem is just a little dealie the size of a pack of cigarettes.  Even though it only has one outgoing RJ-45 it’s sort of a router, in that it can act as a DHCP server.  It would work great if you put a dumb hub on it, which must have been its original design idea.  But my router+base-station is also a DHCP server (and much more) and they were butting heads.  One DHCP server to a network, please!

    I connected my laptop to the modem and input its local IP address in a browser, and told it to chill out and let the fancy router do its thing.  Now my Internet connection is moving faster than ever, so this must have been a long-standing problem.

  3. January 1, 2010 at 02:37 | #3

    A lot of times routing conflicts in SOHO devices can work with degraded performance. Which is nice cause you’re not completely SOL. It sure is a pain in the ass solving degraded performance issues though. Just as hard to get support people to understand the problem too.

    My in laws had the same problem with their setup too. But I got lazy and turned on dynamic routing to solve the problem. Things worked great once I turned on RIP. That was all pretty easy, but changing the addressing scheme on a Netgear router sucks. Not to mention just figuring that much out took awhile too. It kept wanting to go back to a landing page for easy config after I reset it, when I just want to program the damn thing. I recommend Linksys or Dlink, both let you control the changes.

    Anyway with dynamic routing the only thing you need to worry about is that the address range handed out by the mode is different from the wifi router. On anything but a Netgear this is super easy.

    Glad your connection works George! Happy New Year.

  4. January 1, 2010 at 09:05 | #4

    Thanks Webs!  Since I thought the router might be at fault that was the first thing I replaced (and it wasn’t and didn’t solve the problem).  But through dumb luck I replaced it (a NetGear) with a Dlink router so I’m glad to hear your recommendation.

    Now I have a shiny new dual-antenna Dlink N agn router, which is cool because my new laptop has an Atheros ar5b91 chipset that Linux directly supports and which supports n.

    Now I just need me some chrome spinner rims…

  5. January 1, 2010 at 12:57 | #5

    I’ve had good experience with DLink, but when I had the opportunity to get an AirPort Extreme for a good price, I jumped.  The USB port was an additional attraction, so now there is a Fantom 1TB drive attached as a network drive.  That particular model has an N radio but reverts to G if there are any G devices connected.  :(   It also does not have a web interface, which kinda sucks, but the Apple utility works fine.

  6. January 1, 2010 at 13:13 | #6

    LOL George.

    If anyone wants a blazing fast wifi LAN experience with a SOHO wifi router and using n, you should turn off b and g from being used and just use a and n or only n. If this is possible for you… Reason being, both a and n can use the same frequency (5ghz) so bandwidth isn’t throttled back when an a client connects. This assumes of course your SOHO device does not support MIMO and 300mb speeds. Otherwise you would drop from 300mb to around 130mb. The only caveat I add here is that some wifi devices do not support a and only support b/g. So you might inhibit other devices from being able to connect.

    But for most people there likely is little need to mess with this as g still gives 54mb speed. Which is faster than any home connection from an ISP which is usually 10mb at most and if lucky.

  7. January 1, 2010 at 13:35 | #7

    You’re right of course, the DSL connection, even working correctly as it is right now, isn’t a pip on n speed.  Also known as “Ludicrous Speed!”  But the dual antennas should be an advantage given that my base station is in the basement.  I cooked up a super-random encryption password.  You know, added the number “3” to the word “password”  :P

  8. January 1, 2010 at 13:36 | #8

    Oh, and WeeDram has a better use for N than I do, with his wireless NAS.

  9. January 1, 2010 at 18:58 | #9


    That’s the thing you have to look at is what are you doing on your LAN. My friend has a domain at his house with a file server that houses profiles and media. He might have some justification doing a lot of media stuff and needing to pull up profiles with a decent amount of stored content. I haven’t fully gotten into the media stuff myself so I have little use for it. Not to mention the only computer I own with wireless N is a mini from work that I will likely only have for a few more weeks.

    But with newer computers and doing more streaming, I will soon be able to justify the need for N.

  10. January 3, 2010 at 13:16 | #10

    I’ve been having issues lately of, seemingly on a random basis, pages I click on just refuse to load. That’s on my desktop plugged into the router. On the laptop, and iPhone/iTouch, the signal seems at times to be doing fine, then, for no apparent reason, it flops. Losing lots of time on the laptop (not to mention interrupted games) in particular.

    I am not techie enough to know whether this may be the issue you are discussing here, and much too non-techie to attempt the remedy you describe (which is pretty much Greek to me).

    I would humbly accept any help and counsel.

  11. January 3, 2010 at 14:29 | #11

    Gerry:  When a web page won’t load, look at the bottom border and see what it says is happening with the browser.  At my residence in Windsor, I get “looking up www.(something).com” a lot, indicating there’s a DNS issue.  On the same laptop, I have no such problems here in Rochester.  So either my IP config is being served properly in Rochester as opposed to how the router is functioning in Windsor, or my ISP in Windsor has DNS issues.

  12. January 3, 2010 at 14:32 | #12

    I have noticed similar problems too Gerry, but they seem to have all just about dwindled away for me. I haven’t had a problem loading a DOF page in awhile.

    George, when I originally saw the problem it looked like an issue with this site accessing the database. I will leave a comment if I see the issue again, but it’s been at least 3 weeks for me.

  13. January 3, 2010 at 15:37 | #13

    Gerry: Alas I am no expert or I would have figured it out much quicker.  I can only tell you what happened with my network.  Hopefully WeeDram or Webs will correct me if I get any technical details wrong. (They are both network experts)

    First, any device, like a computer or an iPod or a router connected to a local network is called a “Host” and needs an IP (Internet Protocol) address, which is like a phone number, to communicate on the network.

    The address can be hard-set (in the device’s configuration) or it can be automatically “lease” an IP address from a DHCP (Dynamic Host Configuration Protocol) server.

    In addition to whatever other functions it may be serving, any Host that can lease IP addresses to other Hosts is called a “DHCP server”.  Such Hosts can be a router, a modem, a file server, or a special-purpose domain server.

    95% of the computers (Hosts) in the building I work in are set to DHCP, as are all the computers in my house. When they need to lease an IP address, they apply to the DHCP server for one. But which device gets to be the server?

    Suppose there are two DHCP servers on the local network that are engaged in answering IP address leases.  They will get in conflict and connections will drop, and DNS (Domain Name System) requests will get bollixed up.

    Different machines will react differently to this situation.  My Linux machines said; “Looking up ___” but Diane’s Windows machine said; “No Internet connection”.  I don’t know what a Mac would do.

    The solution in our case was to get the DSL modem (and cable modems can also have this function) set to “bridge mode” so it would stop leasing DHCP addresses to hosts in the local network. After that my wireless base station + router (which had DHCP server function) handled leasing addresses just fine.

    With dueling DHCP servers, the symptom was that connection was slow and unreliable, but data transfer was fast once connection was made.  Hope that helps.  I do know that’s just one of several problems that can happen with home networks.

    Try a new cable, for sure.  And make sure your system is running clean.  Any kind of spyware on your desktop machine can make it run flaky.

    Webs, WeeDram, did I get that about right?

  14. January 3, 2010 at 20:56 | #14

    After taking a closer look at Gerry’s comment I realize he seems to be having a general problem. I thought he was originally describing an issue with this website alone. Sorry for that.

    George you described one issue, the one you were having, beautifully. But I think Gerry’s is likely of a different one. Unless his issue does stem from one similar to what you had. Which is a double DHCP/routing issue. If the cable modem and wifi router are both set to DHCP, they are also likely routing traffic. If they hand out addresses in the same network (one is handing out 192.168.0.x and the other is the same) then you have a routing issue. You have two routers routing the same networks, the “0”. It’s okay for both to be handing out DHCP addresses as long as they are handing them out in different networks (change the “0”) and both are set to dynamic routing. But you are correct that setting one of them to bridged mode is the simple thing to do.

    Gerry, correct me if I’m wrong, but it sounds like your issues are only with wifi or wifi seems to be worse? If so you can tweak wifi settings to try to fix the issue. Send me an email if you would like some tips to try (webs05 [at] gmail [dot] com). If wired and wireless are both having issues that seem to be similar and you DO NOT have DSL, try resetting your cable modem and router. If you have DSL, you have settings you need to document first in the modem before resetting.

    If that didn’t work then go to a local computer parts store or Best Buy and purchase a WiFi router, make sure they allow you to return items. Then plug in the new router and see what happens. If things work then your old router was crappin out. If things are still messed up then you may have to contact your ISP and return your new router.

    Let us know what happens…

  15. January 3, 2010 at 21:25 | #15

    Webs, from the description, the problem is happening on both the desktop and wireless.

    Gerry, are your modem and router in one device, or are they two separate devices connected by a cable?

  16. January 3, 2010 at 21:43 | #16

    I wish I were there to do trace routes and additional troubleshooting, maybe even packet capture.  I LOVE packet capture. ;)

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