Checking internet connection without a winbox

Dotan Cohen dotancohen at gmail.com
Sun Jul 2 21:20:34 UTC 2006


On 03/07/06, Les Mikesell <lesmikesell at gmail.com> wrote:
> > Up until here, everything is clear. I also agree that the router
> > shouldn't be droping packets.
>
> Where is 'here'?  If you run traceroute you should see
> each hop separately.

'Here' is up until this point in the letter :)
The rest gets confusing.

> I took your '1.5Mbs' connection to mean a T1 which would normally
> be an interface directly on a router.  If you have a separate
> modem, perhaps you have DSL instead.  Anyway, wiring problems
> are rare but possible.  More likely is a duplex mismatch where
> one end is set to full duplex and one to half.  Check that on
> both the router and PC first. On the linux side, ifconfig will
> show errors and total transmits/receives but you have to do some
> math to compute bandwidth or you can run something like gkrellm
> to show it as a graph.  mii-tool or ethtool will show the
> speed and duplex settings.

I'm on a cable connection. Cable Coming Into House Through Hole In
Wall -> Modem -> Router -> Linbox.

I'll look into the duplex problem, but where do I start? I did a bit
of googling but I apparently don't know which keywords to google. How
can I check linux's duplex setting, and how can I check the routers?
Here, this may help:
$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:C1:26:02:91:50
          inet addr:192.168.123.131  Bcast:192.168.123.255  Mask:255.255.255.0
          inet6 addr: fe80::2c1:26ff:fe02:9150/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:90596 errors:0 dropped:0 overruns:0 frame:0
          TX packets:82693 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:88603039 (84.4 MiB)  TX bytes:12217393 (11.6 MiB)
          Interrupt:11 Base address:0xf00

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:24 errors:0 dropped:0 overruns:0 frame:0
          TX packets:24 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1532 (1.4 KiB)  TX bytes:1532 (1.4 KiB)

> Did you do a 'yum update' immediately after the install?  And if
> you have ssh enabled and reachable from inbound connections, do
> you have a complex password that would be difficult to guess?

The machine is completly up-to-date.

> Try to find something that shows traffic and errors on the router
> side.  And if the errors are on the next hop out past the router,
> report that to your isp.

Wouldn't mtr do that? But I need to correct or eliminate the router first.

Dotan Cohen
http://song-lirics.com




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