[vox-tech] Internet Connectivity Weirdness

[Jeff Newmiller]

Richard S. Crawford wrote:
> On Monday 12 March 2007 02:01:59 am Jeff Newmiller wrote:
> 
>>Richard S. Crawford wrote:
>>
>>>On Sunday 11 March 2007 09:39:29 pm Jeff Newmiller wrote:
>>>
>>>>Richard S. Crawford wrote:
>>>>
>>>>>Over the past few days, I've been unable to reach my work website,
>>>>>http://www.extensiondlc.net, from home.  I can reach just about every
>>>>>other website in the world just fine; it's just that one (and its
>>>>>various subdomains) that are causing the problems.  Furthermore, I can
>>>>>reach the host, http://whsecure.net, just fine, but no subdomains. 
>>>>>This problem is only happening at home.
>>>>>
>>>>>When I try traceroute from any of the computers on my network, I get
>>>>>this:
>>>>>
>>>>>richard at seamus:~
>>>>>$ traceroute extensiondlc.net
>>>>>traceroute to extensiondlc.net (66.232.56.196), 30 hops max, 40 byte
>>>>>packets 1 * * *
>>>>>2 * * *
>>>>>3 * * *
>>>>>4 * * *
>>>>>...
>>>>>30 * * *
>>>>>
>>>>>I get the same output no matter which site I try to traceroute to.
>>>>>
>>>>>In my experience, if I get timeouts at every instance in a traceroute,
>>>>>it means my connection is down; yet, as I mentioned, I can get to just
>>>>>about everywhere on the web except for that one domain just fine.
>>>>>
>>>>>I have already contacted my DSL provider, who insisted (naturally) that
>>>>>nothing was wrong, and that they could not escalate my call.
>>>>>
>>>>>Can anyone offer some insight?\
>>>>
>>>>What is the output of
>>>>
>>>>  netstat -nr
>>>>
>>>>and
>>>>
>>>>  ip link
>>>>
>>>
>>>>from your home machines? Also, what is doing the routing for your
>>>
>>>>home network? One of your linux boxes, or a commercial router?
>>>
>>>richard at seamus:~
>>>$ netstat -nr
>>>Kernel IP routing table
>>>Destination     Gateway         Genmask         Flags   MSS Window  irtt
>>>Iface 192.168.1.0     0.0.0.0         255.255.255.0   U         0 0      
>>>   0 eth0 0.0.0.0         192.168.1.1     0.0.0.0         UG        0 0  
>>>       0 eth0
>>>
>>>richard at seamus:~
>>>$ ip link
>>>1: lo: <LOOPBACK,UP,10000> mtu 16436 qdisc noqueue
>>>    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>>>2: eth0: <BROADCAST,MULTICAST,UP,10000> mtu 1500 qdisc pfifo_fast qlen
>>>1000 link/ether 00:30:bd:b3:f9:2f brd ff:ff:ff:ff:ff:ff
>>>3: sit0: <NOARP> mtu 1480 qdisc noop
>>>    link/sit 0.0.0.0 brd 0.0.0.0
>>>
>>>
>>>I've got a Linksys router doing my routing for me.  :)
>>
>>The fact that the traceroute fails at the Linksys is wierd.
>>If it failed outside your network, I could see the problem being
>>an ISP router issue... but you can't even get a response from
>>your own router.
>>
>>I was hoping an explanation might be found in a dead route to a vpn,
>>but your response above indicates no dead routes on your computer.
>>
>>It is generally best to troubleshoot connectivity problems with
>>IP numbers first... then when all that works, use DNS names to
>>check out your DNS resolution.  Does traceroute work for other
>>public IP addresses?
> 
> 
> Nope, it fails with all public IP addresses.
> 
> If this were a router issue, though, wouldn't I be unable to get out at all?

No... it sounds like something is blocking the traceroute packets, and
I am betting on your Linksys. Note that on windows, tracert uses ICMP
packets, and on *nix uses UDP packets unless you use the "-I" option. [1]
Since http connections use TCP packets, you probably have two different
problems... trying out "-I" and looking through your Linksys configuration
should turn up the problem.

[1] 
http://joesbitbucket.blogspot.com/2006/10/linux-traceroute-vs-windows-tracert.html

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