network woes

[Eric Shubert]

Trent Shipley wrote:
> Eric Shubert wrote:
>> Trent Shipley wrote:
>>> Benjamin Francom wrote:
>>>> On Tue, Dec 22, 2009 at 7:18 PM, Mark Phillips
>>>> <mark at phillipsmarketing.biz> wrote:
>>>>> Trent,
>>>>>
>>>>> I ran into a similar problem today - my network slowed waaaaaaaaaaaaaay down
>>>>> on me. All I used was ping to methodically to check all the connections and
>>>>> found that a switch was reseting itself and dropping packets. Basically, I
>>>>> turn everything off, reset all the routers, cable modems, etc, and then turn
>>>>> on one piece of equipment at a time and ping to the main router to see if I
>>>>> can connect and if there is any packet loss. You can find a out a lot of
>>>>> information by being methodical and knowing your network topology.
>>>>>
>>>>> Good Luck!
>>>>>
>>>>> Mark
>>>>>
>>>>> On Tue, Dec 22, 2009 at 5:52 PM, Trent Shipley <tshipley at deru.com> wrote:
>>>>>> Somewhere my connection to the Internet is borken.  Load times take
>>>>>> forever.  It doesn't seem to effect the wireless client routers, but I
>>>>>> have had trouble on both the wired machines under Ubuntu 9.10 and
>>>>>> Windows Vista.  Sometimes the Linux machine effectively looses
>>>>>> connectivity with the Internet.  It comes back if I log out of my X
>>>>>> session and log back in ... most of the time.  I have a firewall router,
>>>>>> but effectively no household LAN since I've been too lazy to really
>>>>>> figure out how to configure the Ubuntu desktop machine as a primary
>>>>>> domain controller, then adjust it's firewall to suit.
>>>>>>
>>>>>>
>>>>>> I'd like an idiot friendly tool to help track this problem down,
>>>>>> preferably on the Linux machine which seems to experience the problem
>>>>>> most consistently.
>>>>>>
>>>>>> Baring a GUI tool friendly to mortal users, I am not above using the
>>>>>> @#$% command line and a text editor.
>>>>>>
>>>>>>
>>>>>> I am not too network savvy.  I have to look up the layers of the OSI
>>>>>> stack every time.  What is a reasonable diagnostic or fault tree for
>>>>>> approaching my symptoms.
>>>>>>
>>>>>> It is also worth noting that this problem seems to date back to
>>>>>> precisely when I upgraded from Ubuntu 9.04 to 9.10.
>>>>>>
>>>>>> ---------------------------------------------------
>>>>>> PLUG-discuss mailing list - PLUG-discuss at lists.plug.phoenix.az.us
>>>>>> To subscribe, unsubscribe, or to change your mail settings:
>>>>>> http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss
>>>>> ---------------------------------------------------
>>>>> PLUG-discuss mailing list - PLUG-discuss at lists.plug.phoenix.az.us
>>>>> To subscribe, unsubscribe, or to change your mail settings:
>>>>> http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss
>>>>>
>>>> Unplug all devices for at least one min.  Start with modem and work
>>>> your way up to the PC
>>>> The Vista and Ubuntu machines are separate machines, not a single dual
>>>> boot, right?
>>>>
>>>> tracert=windows
>>>> traceroute=linux
>>>> ---------------------------------------------------
>>>> PLUG-discuss mailing list - PLUG-discuss at lists.plug.phoenix.az.us
>>>> To subscribe, unsubscribe, or to change your mail settings:
>>>> http://lists.PLUG.phoenix.az.us/mailman/listinfo/plug-discuss
>>> I have "rebuilt" the network a couple of times from the modem up.  My 
>>> suspicion is focused on the Ubuntu desktop because of the coincidence 
>>> that the problem started with a major upgrade.
>>>
>>> Yes. We have the following on the network ... not all at the same time.
>>> * Qwest modem, outside the firewall.
>>> * Netgear wired/802.11g wireless router. No evident problems with 
>>> wireless connections.
>>> * Ubuntu 9.10 on Dell hardware.  Wired connection. (Main suspect) 
>>> Thinking about putting in a new Ethernet card since I have it "in stock" 
>>> anyway and it's doing me no good in the box.
>>> * Apple notebook.  Wired connection.
>>> ** Windows Vista.  Have seen some symptoms.
>>> ** OS X.  mild symptoms.
>>> * Apple notebook.  Wireless.  No known symptoms.
>>> * Apple iMac. Wireless  No known symptoms.
>>> * (Occasional) HP netbook running Ubuntu 9.10 netbook remix.  Wireless. 
>>>   No known symptoms.
>> That's helpful.
>>
>> I really doubt the upgrade was a cause of any kind, given that your 
>> Apple notebook (other wired) connection also experiences problems.
>>
>> Have you tried alternate wired ports on the Netgear router? Sometimes a 
>> single port/plug can be defective. The whole wired side of the router 
>> might be failing as well.
> 
> I have tried swapping wires and ports.  It doesn't seem to help.
> 
>> Do you have a switch you can put in place of the wireless router to see 
>> if the problem persists?
> 
> I don't have a spare switch.  Of course switches aren't too expensive. 
> I just don't have much use for it outside of testing unless I change my 
> network architecture to something like,
> * Router
> ** Wired switch
> *** wired computers.

I don't think that'll buy you anything, especially if the wired part of 
your router is hosed. I would try something more like this:
* DSL modem
** Wired switch
*** wired computers
*** wireless router

FWIW, this isn't really the best from a security standpoint, but I don't 
think it's any less secure than what you have now.

>> Does your DSL modem do dhcp/nat? (most do these days)
>>
> 
> The DSL modem definitely does dhcp.  I do not know if NAT is being done 
> by the modem or the router.

Probably both. That's not necessarily a problem. You don't want both the 
DSL modem and the router providing dhcp on the same subnet though.

-- 
-Eric 'shubes'