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Ok guys, an update,

When I do the repair I have discovered what is fixing the problem, it
is the clearing of the arp cache.

I know this because I did a manual clear of the arp cache with "arp -d
*" and that fixed it.

I dont know much about arp but hopefully someone here can make some
conclusions about this?

> Explain what equipment. Make, model and exact ways it's all wired together.

Its a Trango Fox 5310 Subscriber Unit. The ethernet cable goes from the
back of the PC into a Power over Ethernet box, out of there and up to
the roof where the Trango is. No routers at my end.

>
> > My PC has been assigned a static IP for the network, and because we are
> > behind a router its not a real world IP.
>
> What static IP? Presumably it's also got static DNS addresses too?

Yep - take a look at a screenshot here:
http://img54.imageshack.us/my.php?image=ss1nr5.jpg


> Repair? With a static IP?

Yep.

>
> When it's working, try opening a cmd prompt and typing "ipconfig /all" and
> post the results here. Then, when it dies, use the same command and see if
> there's *any* differences.

Ok, here it is when its working:
--------------------------------------------------------------------------------------------------------------------------------------------
C:\Documents and Settings\Al>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : al-60c9aaef8b2d
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Marvell Yukon 88E8053 PCI-E
Gigabit
Ethernet Controller
Physical Address. . . . . . . . . : 00-17-31-38-4E-0D
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.252.1
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.252.254
DNS Servers . . . . . . . . . . . : 192.168.252.254
210.55.12.1

Ethernet adapter Bluetooth Network Connection:

Media State . . . . . . . . . . . : Media disconnected
Description . . . . . . . . . . . : Bluetooth Device (Personal
Area Netw
ork)
Physical Address. . . . . . . . . : 00-80-98-44-0B-1D
------------------------------------------------------------------------------------------------------------------------------------------------






>
> When using the ping command, does it always return a successful ping to the
> gateway? Even before doing a repair or disconnect/reconnect of the ethernet
> cable from the PC to the router?

It always sends a successful ping to the gateway when working
(occasionaly 1% loss)

I did try to ping the gateway when the connection when down, and on my
second attempt I got a return, initally I thought it was just the
connection between me the gateway being fixed, but now I think the
whole connection was repaired. Sometimes it fixes itself after a few
minutes - sometimes it takes longer. Have not quite worked this out
exactely yet.

>
> When it's working, what lights are lit on the router *and* on the back of
> the PC? Does your network card in the PC have lights for connection, duplex
> and speed (often color-coded)?

No router involved here - will check the PC.

>
> I'm left wondering if the wireless device isn't doing something to detect
> that the PC is connected and altering the wireless link. As in, it drops
> the internet link based on it thinking the PC isn't there. If that's the
> case then either your PC is "doing something" that confuses the router or
> the router itself is misconfigured or just plain defective.
>
> -Bill Kearney


Thanks Bill - will post the ipconfig /all when its not working....

-Al

PS:

here is my arp -a result before a dropout:

-------------------------------------------------------------------------------------------------------------------------------------------------
C:\Documents and Settings\Al>arp -a

Interface: 192.168.252.1 --- 0x2
Internet Address Physical Address Type
192.168.252.254 00-02-a5-02-44-bd dynamic

------------------------------------------------------------------------------------------------------------------------------------------------

Just waiting for a dropout now......

-Al

In comp.dcom.lans.ethernet Bill Kearney <wkearney-99@hot-mail-com> wrote:

> For the connection from a PC to a router like this that's a useless
> suggestion. Plain old CAT5 would work fine. Presuming it's a good cable of
> course.

I agree, the cable quality doesn't matter much for a short cable,
but I have had some bad cables. Mostly, I believe, the contact
between the cable and the connector, even with commercial cables.

-- glen

In comp.dcom.lans.ethernet wrote:

> When I do the repair I have discovered what is fixing the problem, it
> is the clearing of the arp cache.

In that case, the one answer is another host trying to come
online with the same IP address. The router will then put that
host in its arp table, disconnecting you. Clearing the arp cache
will usually cause your host to arp, adding it to the router arp
table.

One I did see once on a machine with both IP and Appletalk
(ethertalk) was arp replies in both ethernet and SNAP format,
causing the router to switch to SNAP format IP that the host
would then ignore. A ping to any host not in the arp table
would cause a new arp request, and the router would then stop
sending SNAP encapsulated data. That is not likely to be
your problem, though.

-- glen

Ok,

Here ya go, I just lost the connection, and after I lost the
connection, but before I repaired it this is what I got from IPCONFIG
/ALL and ARP -a

C:\Documents and Settings\Al>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : al-60c9aaef8b2d
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Marvell Yukon 88E8053 PCI-E
Gigabit
Ethernet Controller
Physical Address. . . . . . . . . : 00-17-31-38-4E-0D
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 192.168.252.1
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.252.254
DNS Servers . . . . . . . . . . . : 192.168.252.254
210.55.12.1

Ethernet adapter Bluetooth Network Connection:

Media State . . . . . . . . . . . : Media disconnected
Description . . . . . . . . . . . : Bluetooth Device (Personal
Area Netw
ork)
Physical Address. . . . . . . . . : 00-80-98-44-0B-1D

C:\Documents and Settings\Al>arp -a

Interface: 192.168.252.1 --- 0x2
Internet Address Physical Address Type
192.168.252.254 00-02-a5-02-44-bd dynamic

C:\Documents and Settings\Al>arp -d *

HTH?

-Al

One more thing I had a packet sniffer, Ethereal running when it went
down and came back up - not sure if the logs from this will help?

-Al

In comp.dcom.lans.ethernet wrote:
> One more thing I had a packet sniffer, Ethereal running when it went
> down and came back up - not sure if the logs from this will help?

It might.

Better would be the results of arp -a on the router machine
before and after. Otherwise, if there are any arp packets just
before it dies in the ethereal output, post them.

-- glen

On Wed, 3 Jan 2007 09:06:24 -0500, "Bill Kearney"
<wkearney-99@hot-mail-com> wrote:

>> > Unplugging and plugging the ethernet cable back in had the same result
>> > as repair - it allowed me to connect to the internet again.
>> >
>> Hopefully you are using high quality CAT6 cable?
>
>For the connection from a PC to a router like this that's a useless
>suggestion. Plain old CAT5 would work fine. Presuming it's a good cable of
>course.

Agreed. CAT6 is overkill. What limits high speeds is crosstalk (NEXT
and FEXT). For short lengths, such crosstalk is negligible and almost
any type of wire or cable will work.

All of the bad ethernet cables in my palatial office and trucker were
made by me. There should be a clue here, but I'll pretend to ignore
it. Most are visibly defective with:
- creative wiring
- split pairs
- bad crimp
- wrong type of RJ-45 plug
- mangled plastic seperators between pins
- partial crimp
being the main culprits. In general, commercial cables are good
enough.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

On 3 Jan 2007 09:26:27 -0800, wrote:

>When I do the repair I have discovered what is fixing the problem, it
>is the clearing of the arp cache.
>
>I know this because I did a manual clear of the arp cache with "arp -d
>*" and that fixed it.
>
>I dont know much about arp but hopefully someone here can make some
>conclusions about this?

Weird. You didn't answer my question as to whether your wireless ISP
is part of a mesh network. If so, it would make sense that the
destination gateway might change depending on the topology of the
moment. I'll keep things simple and avoid this possibility.

The obvious question is whether the MAC address of the gateway
(192.168.252.254) changes before it disconnects, and after it
recovers. Try it before and after and see if there's a change. If it
does change, well then you'll need to do something to forcibly expire
the arp cache and ping the gateway, which should renew the entry.

However, if it doesn't change, then try this experiment. Run:
arp -s 192.168.252.254 xx-xx-xx-xx-xx-xx
to permanently set the MAC address of the gateway. If this fixes it,
my guess(tm) is that either your ethernet driver or IP stack on your
computah is having a bad day. It's suppose to send an ARP request to
the gateway immediately after it detects a connection. It's not.

I just tried to simulate your problem. I have an ancient DWL-900AP+
setup in client mode connected to the neighbors WRT54G. Encryption is
off. When I disconnect the antenna to simulate a connection loss, it
takes about 2 minutes for XP to recognize that the connection is gone.
Various services (AIM, Skype, PPTP VPN) fail prior to XP announcing a
lost connection.

When I put the antenna back and try to ping the neighbors router, it
takes about 20 seconds to re-establish the connection. Yours
apparently takes either much longer or never succeeds. I just did it
again, but this time, I had a continuously running FPING session
running. The reconnection was about 5 seconds. This is the way it
should work.

>> Explain what equipment. Make, model and exact ways it's all wired together.
>
>Its a Trango Fox 5310 Subscriber Unit. The ethernet cable goes from the
>back of the PC into a Power over Ethernet box, out of there and up to
>the roof where the Trango is. No routers at my end.

Nice:
<http://www.trangobroadband.com/products/fox5310_international.shtml>
5.3GHz. No mesh network. No microwave oven interference. Do you
have line of sight? How far away is the central access point.

>Yep - take a look at a screenshot here:
>http://img54.imageshack.us/my.php?image=ss1nr5.jpg

Perfect. No problems with the IP setup. I can't seem to get the
secondary DNS server to respond to my DNS queries, but it might be
firewalled to accept queries only from the WISP's network.
nslookup
Default Server: dns1.snfcca.sbcglobal.net
Address: 206.13.28.12

> server 201.55.12.1
Default Server: [201.55.12.1]
Address: 201.55.12.1

> www.cruzio.com
Server: [201.55.12.1]
Address: 201.55.12.1

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to [201.55.12.1] timed-out

This is probably unrelated to the current problem, but you should
check if your secondary DNS server is functional from your end.

>It always sends a successful ping to the gateway when working
>(occasionaly 1% loss)

Are the ping times (latency in msec) constant? In other words, do
they always show the same number of msec, or do they vary all over the
place? If they vary, it's a sign of interference or possibly wireless
congestion. The extra delays are signs of packet retransmissions.
Unfortunately, I can't tell where the gateway IP is located in your
WISP's network, so it's difficult to isolate just your traffic
results.

>I did try to ping the gateway when the connection when down, and on my
>second attempt I got a return, initally I thought it was just the
>connection between me the gateway being fixed, but now I think the
>whole connection was repaired. Sometimes it fixes itself after a few
>minutes - sometimes it takes longer. Have not quite worked this out
>exactely yet.

It requires traffic to fix itself. If the arp cache is being flushed,
it won't repopulate the ARP cache untill it sends something to the
gateway. What I find interesting is that the gateway appears to be
functional, but nothing beyond it. Try using traceroute (Windoze
tracert) to something else is going down along the path. It might be
the backhaul between the central access point and where it hits a
wired connection.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

On 3 Jan 2007 11:02:24 -0800, wrote:

>C:\Documents and Settings\Al>arp -a
>
>Interface: 192.168.252.1 --- 0x2
> Internet Address Physical Address Type
> 192.168.252.254 00-02-a5-02-44-bd dynamic

00-02-A5-xx-xx-xx is owned by Compaq Computahs:
<http://www.coffer.com/mac_find/?string=00%3A02%3Aa5>
Well, that makes sense as the gateway is also a DNS server.

From your previous posting, the arp -a results are identical before
and after the disconnect. If you preload the ARP cache with:

arp -s 192.168.252.254 00-02-a5-02-44-bd

methinks I can eliminate the arp cache as a probable culprit and move
onward to whatever is preventing the connection from recovering
gracefully. As far as I can tell, your system is operating normally
except in one respect. It does not recover quickly or gracefully from
a disconnect. I'm still not sure why, but in every other respect, it
functions exactly like my quick test previously mentioned.

Also, I think you would do better to determine (or guess) why the
system is showing disconnects in the first place. My guess(tm) is
some obstructions in the path (trees, cars, excessive path) or
interference from other users of this WISP system.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS