Resetting an external ADSL modem

lorisarvendu wrote:

Mine occasionally drops the line, generally when I'm 10 miles away
trying to connect to it using VNC, and then there's no way of getting
it back up until I get home & restart it using the modem's web
interface.

Or you could just get a better router. I have Verizon DSL, which is
pretty low quality when it comes to uptime and connectedness, but my
router handles it just fine. When I log into my router from a web
browser it allows me to configure settings such as "Reconnect when
disconnected" and "Keep connection alive". This way I don't lose my net
connection for any long periods of time.

On Thu, 05 Feb 2004 22:31:22 +0000, lorisarvendu
wrote:

Hi folks

Has anyone managed to send a software command to an external ADSL
modem/router to reset or reboot it?

You need to determine whether it's the modem, router, or the DSL
service with the problem.

One router make I've seen that had continual crashing problems, is
Belkin.

Mine occasionally drops the line, generally when I'm 10 miles away
trying to connect to it using VNC, and then there's no way of getting
it back up until I get home & restart it using the modem's web
interface.

Are you sure it's the _modem's_ web interface you're restarting, or
the router? If you're on another J(internet) access point, and ping
the router (it's WAN, internet IP address), does it respond?
If your cable modem has diagnostic lights, do they show any difference
when the connection goes down?

You should be able to contact your DSL provider's tech support and
have them try to detect your modem, do so when it's failed.

I had an idea that if I could find a utilty that would ping some
external ip addresses, I could then incorporate this into some kind of
scheduled batch file that would run every 15 mins or so to detect if
the modem was still connected to the 'net. If it detected no
connection it would then send some kind of "reset" command (like an
old modem AT command) to my modem & get it to connect automatically
again.

I've found a ping utility that's just what I need:

http://wettberg.home.texas.net/alive.htm

But I can't seem to find any information about resetting an ADSL
modem. At present the only hint I've got is the "Reset" button on one
of the modem's web pages. Unfortunately it seems to be a java button,
so I can't find any hidden code behind it.

Has anyone else been down this route? The modem's a conexant chipset
(I think) with very minimal instructions, and no support web page, so
I'm reduced to googling.

All the best

Dave

Prices on this type of equipment have dropped a lot in the past year,
you might consider just replacing (whichever is the problem).

"Cyde Weys" said in :
lorisarvendu wrote:

Mine occasionally drops the line, generally when I'm 10 miles away
trying to connect to it using VNC, and then there's no way of getting
it back up until I get home & restart it using the modem's web
interface.

Or you could just get a better router. I have Verizon DSL, which is
pretty low quality when it comes to uptime and connectedness, but my
router handles it just fine. When I log into my router from a web
browser it allows me to configure settings such as "Reconnect when
disconnected" and "Keep connection alive". This way I don't lose my
net connection for any long periods of time.

Your router is on the WAN side of the external ADSL modem? Isn't your
router on the LAN side using its uplink port to go to the modem? If so, how
are you going to browse to your router from the Internet (presuming you have
enabled it for remote connect using a strong password) when the intervening
ADSL modem is dead? The IP address assigned to the router's WAN side by
your ISP's DHCP server won't be known to you. Even if you record the IP
address assigned to the WAN side of your router, that IP address expires and
if you lose the connection then the ADSL will use its internal DHCP server
to assign temporary IP addresses (to your router, like 192.168.100.1). I
actually use a cable connection and that's why the cable modem will do when
it loses its connection. If the connection is lost to the ADSL modem,
you're not going to be able to connect to it or the router on its LAN side.

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*Vanguard* wrote:

Your router is on the WAN side of the external ADSL modem? Isn't your
router on the LAN side using its uplink port to go to the modem? If so, how
are you going to browse to your router from the Internet (presuming you have
enabled it for remote connect using a strong password) when the intervening
ADSL modem is dead? The IP address assigned to the router's WAN side by
your ISP's DHCP server won't be known to you. Even if you record the IP
address assigned to the WAN side of your router, that IP address expires and
if you lose the connection then the ADSL will use its internal DHCP server
to assign temporary IP addresses (to your router, like 192.168.100.1). I
actually use a cable connection and that's why the cable modem will do when
it loses its connection. If the connection is lost to the ADSL modem,
you're not going to be able to connect to it or the router on its LAN side.

You're absolutely correct, I am not able to connect to my router from
outside when the connection is down. But I never claimed I was able to,
and in any case, that's not necessary. My router detects when the
internet connection goes down and automatically tells the DSL modem to
reconnect, so I don't need to be able to access it remotely to tell it
to recconect; it does that automagically.

"Cyde Weys" said in :
*Vanguard* wrote:
[snip]
My router detects when the
internet connection goes down and automatically tells the DSL modem to
reconnect, so I don't need to be able to access it remotely to tell it
to recconect; it does that automagically.

Reconnect? How? By doing a DHCP release and renew (from the router to see
if that will kick the modem in the butt when the connection eventually and
hopefully comes back to reconnect back the ISP's DHCP server)?

What router do you use? I'd like to visit their web page for the product to
see if they describe how their router can force the cable/DSL modem to
perform a "reconnect". Or see if they had downloadable manuals that would
explain it.



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*Vanguard* wrote:

What router do you use? I'd like to visit their web page for the product to
see if they describe how their router can force the cable/DSL modem to
perform a "reconnect". Or see if they had downloadable manuals that would
explain it.

Hell if I know. Both of my routers (an old Linksys and a somewhat new
D-Link wireless) had this feature. I thought most routers had this
feature. Or maybe I'm mistaken as to what it actually does?

"Cyde Weys" said in :
*Vanguard* wrote:

What router do you use? I'd like to visit their web page for the
product to see if they describe how their router can force the
cable/DSL modem to perform a "reconnect". Or see if they had
downloadable manuals that would explain it.

Hell if I know. Both of my routers (an old Linksys and a somewhat new
D-Link wireless) had this feature. I thought most routers had this
feature. Or maybe I'm mistaken as to what it actually does?

I have the DLink DI-604. Nothing fancy but sufficient for home use and has
a firewall built in (useful only against external attacks so I still use
software firewalls). It has a feature where you can reboot it (without
having to walk over to it).

It also had "DHCP Release" and "DHCP Renew". Those are equivalant to
running "ipconfig /release *" and "ipconfig /renew" on your computer.
However, with the router in the way, these only have the computer request
the router's DHCP server to issue a new IP address to the computer, not your
ISP's DHCP server.

My cable modem (Motorola) also has a DHCP server but it is used only when
the connection is lost to the ISP. When the connection is lost, the cable
modem's DHCP server will assign IP addresses starting from 192.168.100.11 to
192.168.100.254. It doesn't know you have a router with a DHCP server doing
that job. The cable modem's DHCP server goes active after a lost connection
so your hosts continue to function under TCP because they will get their
dynamically assigned IP addresses from the cable modem. This backup DHCP
server in the cable modem is superfluous if you are using a router after it
that uses its DHCP server. With the router in the way, all this ends up
doing is having the cable modem assign 192.168.100.11 to the WAN side of the
router. If I ever look at the router's status web page and see that IP
address assigned to its WAN side, I know that the connection from the cable
modem to my ISP went dead but I don't know if it is still dead. Peculiarly,
when the connection comes back, my router may still have the 192.168.100.11
IP address assigned to it. There's nothing I can think of that will let the
cable modem kick the router in the butt to let it know the Internet
connection came back. The clients request the IP address. I don't think
the DHCP server (in the cable modem) can force the clients to request a new
one. Since the router isn't assigned an IP address that my ISP allows on
their network, and since I'm still not using my ISP's DHCP server to allow
it to assign the gateway and DNS servers' IP addresses (to the router), I
still cannot connect to the Internet. I have to force the router to
relinquish its IP address it got during the outage from the cable modem's
DHCP server and request a new one from my ISP's DHCP server. That's why the
router must have the release and renew functions in it somewhere. Maybe
that's what you thought was a reconnect. The router would have to know that
certain IP ranges were being assigned by the cable/DSL modem's DHCP server
rather than the ISP's DHCP server and then periodically keep trying to
repeat a release and renew to see if it got an IP address outside that range
(i.e., from the ISP's DHCP server). I don't remember seeing a feature like
this but it sounds doable as long as you can configure the IP ranges for the
"lost connection" state that would be from something other than your ISP's
DHCP server.

A buddy of mine just got the Linksys BEFSX41 (although I told him to return
it for something else since I've heard bad things about it in the
newsgroups). Its manual mentions the Keep-Alive function. My DLink's setup
doesn't show that option so I don't know if it has it or it is built-in and
fixed to always run. However, Keep-Alive is the VPN connections. If the
VPN connection drops then it tries to reestablish it. I doubt it can spur a
reconnect to your ISP's network in trying to reestablish a VPN connection.
Instead, I suspect it just gets continual errors because the base network
(i.e., Internet) used to carry the VPN connection is not available. I'm
wondering if that's what you thought would force a reconnect of the router
to the modem (i.e., the router drops its modem's DHCP assigned IP address
and renews with the ISP's DHCP server for an IP address).

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"lorisarvendu" said in :

I've just found, buried deep down in the web interface, a small tick
box for "Automatic Reconnect". Which was unticked.

This of course means that I am an arse.

Many apologies for wasting your time, and thanks for all the advice.
I shall now go and stick my head in a bucket.


Which aDSL modem do you have? I'd like to visit the maker's web site to see
if they have info or it is mentioned in a downloadable copy of its manual as
to what this Automatic Reconnect does and how it works. Is there also a
Restart or Reboot modem function besides the Auto Reconnect?

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"*Vanguard*" said in :
"lorisarvendu" said in
:

I've just found, buried deep down in the web interface, a small tick
box for "Automatic Reconnect". Which was unticked.

This of course means that I am an arse.

Many apologies for wasting your time, and thanks for all the advice.
I shall now go and stick my head in a bucket.


Which aDSL modem do you have? I'd like to visit the maker's web site
to see if they have info or it is mentioned in a downloadable copy of
its manual as to what this Automatic Reconnect does and how it works.
Is there also a Restart or Reboot modem function besides the Auto
Reconnect?

Oops for me, too. I did some Google searching and read a couple articles
which then led me to believe that the Auto Reconnect in the routers is only
applicable and available when configuring it to use PPoE (which is used to
connect the router to an aDSL modem). I'm using a cable modem. If I select
PPoE then I see the Auto Reconnect option. So apparently DSL modems have a
feature to force them to try to reconnect (but that also hints that it
happens a lot).

Also, when I select PPoE, other fields appear to enter the username and
password. So although DSL doesn't do dial-up like an analog modem to
handshake with another analog modem, there still seems to be the need to
establish a session. So if the session gets dropped then the connection
gets dropped and thus the need to Auto Reconnect.

Learn something new every day. However, trying to get low-level hardware
information regarding exactly how aDSL makes a connection has proven elusive
so far. Articles expend a great deal of words describing its features and
operation but at a blackbox level. I didn't realize ISDN, another digital
service, actually does a dial-up to make a connection but you don't notice
it because it happens in a second.


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