A Broadband and ADSL forum. BroadbanterBanter

Welcome to BroadbanterBanter.

You are currently viewing as a guest which gives you limited access to view most discussions and other FREE features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload your own photos and access many other special features. Registration is fast, simple and absolutely free so please, join our community today.

Go Back   Home » BroadbanterBanter forum » Newsgroup Discussions » uk.telecom.broadband (UK broadband)
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

uk.telecom.broadband (UK broadband) (uk.telecom.broadband) Discussion of broadband services, technology and equipment as provided in the UK. Discussions of specific services based on ADSL, cable modems or other broadband technology are also on-topic. Advertising is not allowed.

Detecting loss of ADSL & switchover to 3G



 
 
Thread Tools Display Modes
  #1  
Old July 17th 13, 07:22 AM posted to uk.telecom.broadband
Peter
external usenet poster
 
Posts: 330
Default Detecting loss of ADSL & switchover to 3G



We have an ADSL connection at work, with a 3G backup.

The ISP (a supposedly high quality specialist business ISP) gives us a
number of fixed IPs, which are supposed to get rerouted to the 3G if
the ADSL fails.

If I power down the ADSL modem, it all works fine. The router detects
the loss of the WAN1 ("ethernet") service and switches over to WAN1
("3G") which is a USB 3G adaptor. When the ADSL has been back up for 2
minutes, the 3G is shut down and it switches back to the ADSL.

We pay just 2.50/month for the 3G backup so this is pretty good. We
pay about 40/month for the whole thing including an 800kbits/sec UP
speed (8M down; the exchange doesn't do the 20mb).

However we have had several losses of ADSL where the 3G backup did not
work. The ISP is pretty arrogant about it (seems to be their in-house
operating mode) and blame it on our equipment. However on the last-1
time it happened (weekend as usual) I did go to the office and found
that the IP had changed... this is OK for outgoing stuff but obviously
any incoming connections (RDP, VPN, etc) will fail.

The ISP claims this cannot happen with their equipment because they
allocate fixed IPs. But this is self evidently ********. The IP is
allocated (DHCP) by the DHCP server in the ISP's router, and customers
who pay for a fixed IP just happen to get the same IP every time. Or
maybe not....

The Q is how could one possibly detect such a scenario i.e. where you
have one of these cases

1) the ADSL connection seems OK (how the Draytek router detects the
failure of WAN1 is undocumented) and the break in connectivity is
further upstream (usually blamed on British Telecom) or

2) the ADSL connection works but the IP has been changed

The router can't be configured to periodically check an external
website and check it's own IP.

We could dump this ISP but they all seem to have these problems from
time to time. The only ISP I know of which has had zero downtime for
years is ZEN (a really brilliant company) but I can't use them at work
because we use them at home and that is where the backup server
(rsynced from the office one every night) is located!

There are services which can detect external loss of connectivity but
how can one use that to switch over the router to use the 3G adapter?

Especially when the router is then not accessible remotely, due to the
loss of connectivity!

I imagine there are high-end solutions for this, but what's really
needed (for cheap people like me - our router is the 300 Draytek
2955) is some means whereby the router can detect that full
connectivity has been lost, or the IP has changed.

I think all the Draytek routers do is they look for a loss of some
kind of regular keep-alive packet which passes between the ADSL gear
in the telephone exchange, and the router (or maybe the ADSL modem - a
Draytek 120). All that will detect is a physical loss of the ADSL
connection to the exchange.

One gets a related sort of issue with say a smartphone with the WIFI
enabled and configured to connect automatically, and also 3G enabled.
All the time it is picking up unencrypted WIFI access points, it won't
use the 3G - because it is too stupid to actually check connectivity
all the way out by e.g. checking if google.com can be accessed. And
because nearly all the WIFI APs are commercial "pay" ones, nothing
works... Satellite phones also frequently suffer from a "perfect data
connection" (you get DHCP etc etc) but no data will come through.

I can get two different ISPs to give us two ADSL services, and the
router will switch between the two, but (a) the criteria for the
fallover won't be any more intelligent and (b) we obviously can't have
the same IPs from both.

I wonder how this is solved professionally. An external monitoring
service, sending an SMS to the router and switching it over? Or maybe
a clever router which communicates with an external service
periodically and gets it to check incoming connection?
  #2  
Old July 17th 13, 09:37 AM posted to uk.telecom.broadband
Graham J
external usenet poster
 
Posts: 620
Default Detecting loss of ADSL & switchover to 3G

Comments in-line ...

Peter wrote:


We have an ADSL connection at work, with a 3G backup.

The ISP (a supposedly high quality specialist business ISP) gives us a
number of fixed IPs, which are supposed to get rerouted to the 3G if
the ADSL fails.


Is this A&A ???

How does the ISP know that your ADSL has failed?

If I power down the ADSL modem, it all works fine. The router detects
the loss of the WAN1 ("ethernet") service and switches over to WAN1


Do you mean WAN2 ????

Does it also recognise when you unplug the phone wire from the ADSL modem?

("3G") which is a USB 3G adaptor. When the ADSL has been back up for 2
minutes, the 3G is shut down and it switches back to the ADSL.

We pay just 2.50/month for the 3G backup so this is pretty good. We
pay about 40/month for the whole thing including an 800kbits/sec UP
speed (8M down; the exchange doesn't do the 20mb).

However we have had several losses of ADSL where the 3G backup did not
work. The ISP is pretty arrogant about it (seems to be their in-house
operating mode) and blame it on our equipment. However on the last-1
time it happened (weekend as usual) I did go to the office and found
that the IP had changed... this is OK for outgoing stuff but obviously
any incoming connections (RDP, VPN, etc) will fail.


Do you mean the WAN1 IP address for ADSL had changed?

The ISP claims this cannot happen with their equipment because they
allocate fixed IPs. But this is self evidently ********. The IP is
allocated (DHCP) by the DHCP server in the ISP's router, and customers
who pay for a fixed IP just happen to get the same IP every time. Or
maybe not....


A fault in the BT network can cause this. Normally the PPP
authentication is passed through the BT network to a (Radius) server at
your ISP, where your username and password are recognised and your ISP
issues a (consistent) IP address. If the BT network has a problem, then
your ISP's Radius server is not accessible and BT issues your router
with a substitute IP address. This is normally sufficient to run
diagnostics but the BT DNS server thereby made available to you
deliberately does not resolve most names: thereby limiting access to BT
websites only.

When this fault occurred, what IP address were you allocated? Was it
one from the range allocated to your ISP?

The Q is how could one possibly detect such a scenario i.e. where you
have one of these cases

1) the ADSL connection seems OK (how the Draytek router detects the
failure of WAN1 is undocumented)


No - surely it should be clear from the configuration of the router!

and the break in connectivity is
further upstream (usually blamed on British Telecom) or

2) the ADSL connection works but the IP has been changed

The router can't be configured to periodically check an external
website and check it's own IP.

We could dump this ISP but they all seem to have these problems from
time to time. The only ISP I know of which has had zero downtime for
years is ZEN (a really brilliant company) but I can't use them at work
because we use them at home and that is where the backup server
(rsynced from the office one every night) is located!

There are services which can detect external loss of connectivity but
how can one use that to switch over the router to use the 3G adapter?

Especially when the router is then not accessible remotely, due to the
loss of connectivity!

I imagine there are high-end solutions for this, but what's really
needed (for cheap people like me - our router is the 300 Draytek
2955) is some means whereby the router can detect that full
connectivity has been lost, or the IP has changed.

I think all the Draytek routers do is they look for a loss of some
kind of regular keep-alive packet which passes between the ADSL gear
in the telephone exchange, and the router (or maybe the ADSL modem - a
Draytek 120). All that will detect is a physical loss of the ADSL
connection to the exchange.


You could try the Draytek 2830. On this the WAN1 port is an ADSL modem,
and the failover detection can be configured for either ARP or ping to
an IP. Normally you would choose ARP, but all this will prove is that
the ADSL has connectivity. If you choose Ping and specify the static IP
address that you know the ADSL port should have, then a failure such as
I describe above would cause failover to 3G.

Does your 3G backup have the same IP address as the ADSL service? If
not, how do you use RDP and VPN during failover?

From what you wrote above, the backup 3G service does use the same IP
address. So any failover detection mechanism relying on IP addresses
will fail.

One gets a related sort of issue with say a smartphone with the WIFI
enabled and configured to connect automatically, and also 3G enabled.
All the time it is picking up unencrypted WIFI access points, it won't
use the 3G - because it is too stupid to actually check connectivity
all the way out by e.g. checking if google.com can be accessed. And
because nearly all the WIFI APs are commercial "pay" ones, nothing
works... Satellite phones also frequently suffer from a "perfect data
connection" (you get DHCP etc etc) but no data will come through.

I can get two different ISPs to give us two ADSL services, and the
router will switch between the two, but (a) the criteria for the
fallover won't be any more intelligent and (b) we obviously can't have
the same IPs from both.


I wonder how this is solved professionally. An external monitoring
service, sending an SMS to the router and switching it over? Or maybe
a clever router which communicates with an external service
periodically and gets it to check incoming connection?


Multiple ISPs and a router running BGP. Think Cisco and 5,000 upwards.
This is what ISPs themselves do, and businesses who host websites.

You could script a telnet session to interrogate the router for its WAN
IP address, to verify that it is the address it ought to be. Run this
once every minute, and get it to email/sms if a mismatch is ever seen.
Make the script write its results to a log file so you have the evidence
for your ISP.


--
Graham J


  #3  
Old July 17th 13, 10:29 AM posted to uk.telecom.broadband
The Natural Philosopher
external usenet poster
 
Posts: 2,728
Default Detecting loss of ADSL & switchover to 3G

On 17/07/13 07:22, Peter wrote:
I wonder how this is solved professionally.


at huge cost and complexity.

What you want is e.g a fixed IP address that you own, that is part of
the GLOBAL BGP tables, so that its route can be advertised by e.g. two
different ISPs depending on who has the best route to you.

Thats a BBC.co.uk type solution, not joe-soap.co.uk


You are frankly asking a lot to expect established sessions to survive a
route switch. IF your ISP is offering this as a bundle, then they ought
to be able to manage it.

They should be big enough.


An external monitoring
service, sending an SMS to the router and switching it over? Or maybe
a clever router which communicates with an external service
periodically and gets it to check incoming connection?

No, do it via the ISP, and if they are not doing it, find someone who will.



--
Ineptocracy

(in-ep-toc'-ra-cy) - a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

  #4  
Old July 17th 13, 05:56 PM posted to uk.telecom.broadband
Peter
external usenet poster
 
Posts: 330
Default Detecting loss of ADSL & switchover to 3G


Graham J [email protected] wrote

Comments in-line ...

Peter wrote:


We have an ADSL connection at work, with a 3G backup.

The ISP (a supposedly high quality specialist business ISP) gives us a
number of fixed IPs, which are supposed to get rerouted to the 3G if
the ADSL fails.


Is this A&A ???


Yes.

How does the ISP know that your ADSL has failed?


They can tell if I pull the plug on the ADSL modem. I get an SMS
telling me ADSL has failed. And the router switches over to 3G because
it detects WAN1 is down.

If I power down the ADSL modem, it all works fine. The router detects
the loss of the WAN1 ("ethernet") service and switches over to WAN1


Do you mean WAN2 ????


Yes; sorry.

Does it also recognise when you unplug the phone wire from the ADSL modem?


Yes I think so. Normally, to test this, I switch off the ADSL modem.

("3G") which is a USB 3G adaptor. When the ADSL has been back up for 2
minutes, the 3G is shut down and it switches back to the ADSL.

We pay just 2.50/month for the 3G backup so this is pretty good. We
pay about 40/month for the whole thing including an 800kbits/sec UP
speed (8M down; the exchange doesn't do the 20mb).

However we have had several losses of ADSL where the 3G backup did not
work. The ISP is pretty arrogant about it (seems to be their in-house
operating mode) and blame it on our equipment. However on the last-1
time it happened (weekend as usual) I did go to the office and found
that the IP had changed... this is OK for outgoing stuff but obviously
any incoming connections (RDP, VPN, etc) will fail.


Do you mean the WAN1 IP address for ADSL had changed?


Yes. To something random.

The ISP claims this cannot happen with their equipment because they
allocate fixed IPs. But this is self evidently ********. The IP is
allocated (DHCP) by the DHCP server in the ISP's router, and customers
who pay for a fixed IP just happen to get the same IP every time. Or
maybe not....


A fault in the BT network can cause this. Normally the PPP
authentication is passed through the BT network to a (Radius) server at
your ISP, where your username and password are recognised and your ISP
issues a (consistent) IP address. If the BT network has a problem, then
your ISP's Radius server is not accessible and BT issues your router
with a substitute IP address. This is normally sufficient to run
diagnostics but the BT DNS server thereby made available to you
deliberately does not resolve most names: thereby limiting access to BT
websites only.


Interesting... I had a recent case where we got full outgoing
functionality, on the "random" IP.

When this fault occurred, what IP address were you allocated? Was it
one from the range allocated to your ISP?


I don't recall, but it was very different from what it shoul dbe.

The Q is how could one possibly detect such a scenario i.e. where you
have one of these cases

1) the ADSL connection seems OK (how the Draytek router detects the
failure of WAN1 is undocumented)


No - surely it should be clear from the configuration of the router!


I cannot find it in the config of the router (2955). Most likely it is
accessible if you telnet into it and hack around the unix stuff, but
it isn't apparent in the GUI.

There is a separate config for a fallover if more bandwidth is needed.

This is the WAN2 menu (if you can read it)

Enable: YesNo
Display Name:
Physical Mode: Ethernet
Physical Mode: Ethernet3G USB Modem
Physical Type: Auto negotiation10M half duplex10M full duplex100M half duplex100M full duplex
Load Balance Mode: Auto WeightAccording to Line Speed
Line Speed(Kbps): DownLink
UpLink
Active Mode: Always OnActive on demand
Active on demand:
WAN1 Fail
WAN1 Upload speed exceed Kbps
WAN1 Download speed exceed Kbps


What "WAN1 fail" means is unclear.

and the break in connectivity is
further upstream (usually blamed on British Telecom) or

2) the ADSL connection works but the IP has been changed

The router can't be configured to periodically check an external
website and check it's own IP.

We could dump this ISP but they all seem to have these problems from
time to time. The only ISP I know of which has had zero downtime for
years is ZEN (a really brilliant company) but I can't use them at work
because we use them at home and that is where the backup server
(rsynced from the office one every night) is located!

There are services which can detect external loss of connectivity but
how can one use that to switch over the router to use the 3G adapter?

Especially when the router is then not accessible remotely, due to the
loss of connectivity!

I imagine there are high-end solutions for this, but what's really
needed (for cheap people like me - our router is the 300 Draytek
2955) is some means whereby the router can detect that full
connectivity has been lost, or the IP has changed.

I think all the Draytek routers do is they look for a loss of some
kind of regular keep-alive packet which passes between the ADSL gear
in the telephone exchange, and the router (or maybe the ADSL modem - a
Draytek 120). All that will detect is a physical loss of the ADSL
connection to the exchange.


You could try the Draytek 2830. On this the WAN1 port is an ADSL modem,
and the failover detection can be configured for either ARP or ping to
an IP. Normally you would choose ARP, but all this will prove is that
the ADSL has connectivity. If you choose Ping and specify the static IP
address that you know the ADSL port should have, then a failure such as
I describe above would cause failover to 3G.


Hmmm... the 2955 costs even more than the 2830 I think

That's interesting.

Does your 3G backup have the same IP address as the ADSL service? If
not, how do you use RDP and VPN during failover?


It does - if the ISP has configured it right. It wasn't done
initially.

From what you wrote above, the backup 3G service does use the same IP
address. So any failover detection mechanism relying on IP addresses
will fail.


I think, however, that the 3G is dead if WAN1 is working. I think the
ISP activates the 3G account, and routes the IPs to it, only when
*they* are aware the ADSL has failed.

Now we are onto the question as to how the *ISP* knows ADSL has
failed!

If I pull the ADSL modem, they know right away.

On the last failure (13th July, no 3G failover) I got no SMS from
them, but they told me they don't send them out if the issue is
widespread.

One gets a related sort of issue with say a smartphone with the WIFI
enabled and configured to connect automatically, and also 3G enabled.
All the time it is picking up unencrypted WIFI access points, it won't
use the 3G - because it is too stupid to actually check connectivity
all the way out by e.g. checking if google.com can be accessed. And
because nearly all the WIFI APs are commercial "pay" ones, nothing
works... Satellite phones also frequently suffer from a "perfect data
connection" (you get DHCP etc etc) but no data will come through.

I can get two different ISPs to give us two ADSL services, and the
router will switch between the two, but (a) the criteria for the
fallover won't be any more intelligent and (b) we obviously can't have
the same IPs from both.


I wonder how this is solved professionally. An external monitoring
service, sending an SMS to the router and switching it over? Or maybe
a clever router which communicates with an external service
periodically and gets it to check incoming connection?


Multiple ISPs and a router running BGP. Think Cisco and 5,000 upwards.
This is what ISPs themselves do, and businesses who host websites.

You could script a telnet session to interrogate the router for its WAN
IP address, to verify that it is the address it ought to be. Run this
once every minute, and get it to email/sms if a mismatch is ever seen.
Make the script write its results to a log file so you have the evidence
for your ISP.


I think there are services that can monitor a website and send an SMS
if duff, etc.

I ought to set that up, because we will have an online shop soon also.
  #5  
Old July 17th 13, 10:58 PM posted to uk.telecom.broadband
Graham J
external usenet poster
 
Posts: 620
Default Detecting loss of ADSL & switchover to 3G

More comments in-line[snip]

Is this A&A ???


Yes.


Generally recognised as the best ...

How does the ISP know that your ADSL has failed?


They can tell if I pull the plug on the ADSL modem. I get an SMS
telling me ADSL has failed. And the router switches over to 3G because
it detects WAN1 is down.

If I power down the ADSL modem, it all works fine. The router detects
the loss of the WAN1 ("ethernet") service and switches over to WAN1


Do you mean WAN2 ????


Yes; sorry.

Does it also recognise when you unplug the phone wire from the ADSL modem?


Yes I think so. Normally, to test this, I switch off the ADSL modem.


Please test this and report back.

[snip]

The ISP claims this cannot happen with their equipment because they
allocate fixed IPs. But this is self evidently ********. The IP is
allocated (DHCP) by the DHCP server in the ISP's router, and customers
who pay for a fixed IP just happen to get the same IP every time. Or
maybe not....


No, the DHCP server recognises the MAC address of your router and issues
the IP address specifed for that MAC address. Unless their DHCP server
is faulty ....


A fault in the BT network can cause this. Normally the PPP
authentication is passed through the BT network to a (Radius) server at
your ISP, where your username and password are recognised and your ISP
issues a (consistent) IP address. If the BT network has a problem, then
your ISP's Radius server is not accessible and BT issues your router
with a substitute IP address. This is normally sufficient to run
diagnostics but the BT DNS server thereby made available to you
deliberately does not resolve most names: thereby limiting access to BT
websites only.


Interesting... I had a recent case where we got full outgoing
functionality, on the "random" IP.

When this fault occurred, what IP address were you allocated? Was it
one from the range allocated to your ISP?


I don't recall, but it was very different from what it should be.


Please make sure you note it down next time the fault occurs. Then use a
Whois service to find who owns it.

Report it to A&A - they should be able to interrogate their DHCP server
and confirm the address they issued matches the one you report.

The Q is how could one possibly detect such a scenario i.e. where you
have one of these cases

1) the ADSL connection seems OK (how the Draytek router detects the
failure of WAN1 is undocumented)


No - surely it should be clear from the configuration of the router!


I cannot find it in the config of the router (2955). Most likely it is
accessible if you telnet into it and hack around the unix stuff, but
it isn't apparent in the GUI.


I have here a V2910. Basically an earlier and simpler version of your 2955.

Under WAN - Internet Access - on the screen where you set the PPPoE
Client mode and ISP Access Setup, the lower part of the screen shows
"WAN Connection Detection" and you can select either ARP or PING. I
suspect the V2955 must have a similar screen.

[snip]

Hmmm... the 2955 costs even more than the 2830 I think


What do you need from the 2955 that is not provided by the 2830?

I think, however, that the 3G is dead if WAN1 is working. I think the
ISP activates the 3G account, and routes the IPs to it, only when
*they* are aware the ADSL has failed.

Now we are onto the question as to how the *ISP* knows ADSL has
failed!

If I pull the ADSL modem, they know right away.


Because A&A use LCP monitoring - this confirms packet exchange between
you and them, irrespective (I think) of the IP address allocated to your
router.

So the issue is the allocation of the "incorrect" IP address. I think
you need to escalate this within A&A, and ask them to lend you one of
their routers to confirm whether the fault can then be demonstrated to
occur.

If only your equipment demonstrates the problem, complain to Draytek.

--
Graham J



  #6  
Old July 18th 13, 07:39 AM posted to uk.telecom.broadband
Andy Burns
external usenet poster
 
Posts: 75
Default Detecting loss of ADSL & switchover to 3G

Graham J wrote:

The ISP claims this cannot happen with their equipment because they
allocate fixed IPs. But this is self evidently ********. The IP is
allocated (DHCP) by the DHCP server in the ISP's router, and customers
who pay for a fixed IP just happen to get the same IP every time. Or
maybe not....


No, the DHCP server recognises the MAC address of your router and issues
the IP address specifed for that MAC address. Unless their DHCP server
is faulty ....


What "MAC address" would the router use when falling back to the USB
dongle? How would the ISP recognise this as the same when using the WAN1
port?


  #7  
Old July 18th 13, 08:00 AM posted to uk.telecom.broadband
Peter
external usenet poster
 
Posts: 330
Default Detecting loss of ADSL & switchover to 3G



Yes I think so. Normally, to test this, I switch off the ADSL modem.


Please test this and report back.


Will do.

No, the DHCP server recognises the MAC address of your router and issues
the IP address specifed for that MAC address. Unless their DHCP server
is faulty ....


I don't see how it can be doing that since I have two identically
configured 2955s (but their MAC addresses can't be the same) which I
can swap and everything works as before.

I also have two of the Draytek 120 modems (which have no config) and
can swap them around. They do sometimes pack up.

Please make sure you note it down next time the fault occurs. Then use a
Whois service to find who owns it.

Report it to A&A - they should be able to interrogate their DHCP server
and confirm the address they issued matches the one you report.


I asked them if you could look at their logs to see why the 3G failed
on the 13th. The man refused to do anything about it.

The Q is how could one possibly detect such a scenario i.e. where you
have one of these cases

1) the ADSL connection seems OK (how the Draytek router detects the
failure of WAN1 is undocumented)

No - surely it should be clear from the configuration of the router!


I cannot find it in the config of the router (2955). Most likely it is
accessible if you telnet into it and hack around the unix stuff, but
it isn't apparent in the GUI.


I have here a V2910. Basically an earlier and simpler version of your 2955.

Under WAN - Internet Access - on the screen where you set the PPPoE
Client mode and ISP Access Setup, the lower part of the screen shows
"WAN Connection Detection" and you can select either ARP or PING. I
suspect the V2955 must have a similar screen.


Oh yes!

WAN Connection Detection
Mode ARP DetectPing Detect
Ping IP
TTL:

Currenly it is set to ARP detect.

So it looks like I could ping a specific external IP.

What does the TTL parameter do? Is it the number of seconds between
pings?

If I put in the IP we *should* be getting allocated by the ISP, does
that actually check anything useful? I wonder if it would just do a
local loopback i.e. useless.

[snip]

Hmmm... the 2955 costs even more than the 2830 I think


What do you need from the 2955 that is not provided by the 2830?


I can't recall why we bought it.

SSL VPN perhaps?

I think, however, that the 3G is dead if WAN1 is working. I think the
ISP activates the 3G account, and routes the IPs to it, only when
*they* are aware the ADSL has failed.

Now we are onto the question as to how the *ISP* knows ADSL has
failed!

If I pull the ADSL modem, they know right away.


Because A&A use LCP monitoring - this confirms packet exchange between
you and them, irrespective (I think) of the IP address allocated to your
router.

So the issue is the allocation of the "incorrect" IP address. I think
you need to escalate this within A&A, and ask them to lend you one of
their routers to confirm whether the fault can then be demonstrated to
occur.

If only your equipment demonstrates the problem, complain to Draytek.


They have offered a box called a "Firebrick" but I don't want to be
spending yet more of my time (probably days; it usually works out like
that) setting that up. This is supposed to work...

The outage with an IP change is very rare but next time I will make a
note of what it is. It just means I have to go there physically,
because RDP doesn't work.

We have used Clara, Eclipse, and now A&A. All have about the same
downtime rate. Always blamed on BT. Downtime on ZEN has been zero IIRC
over maybe 10 years. All these are on the same exchange (01273). The
others used to change the "fixed" IP too. Eclipse used to do it quite
a lot.
  #8  
Old July 18th 13, 08:12 AM posted to uk.telecom.broadband
Graham J
external usenet poster
 
Posts: 620
Default Detecting loss of ADSL & switchover to 3G

Andy Burns wrote:
Graham J wrote:

The ISP claims this cannot happen with their equipment because they
allocate fixed IPs. But this is self evidently ********. The IP is
allocated (DHCP) by the DHCP server in the ISP's router, and customers
who pay for a fixed IP just happen to get the same IP every time. Or
maybe not....


No, the DHCP server recognises the MAC address of your router and issues
the IP address specifed for that MAC address. Unless their DHCP server
is faulty ....


What "MAC address" would the router use when falling back to the USB
dongle? How would the ISP recognise this as the same when using the WAN1
port?


I was wrong. What I described is how DHCP reservations work on a LAN.

I imagine the IP address is looked up from the account parameters when
the PPP sessions starts.

--
Graham J

  #9  
Old July 18th 13, 08:29 AM posted to uk.telecom.broadband
Graham J
external usenet poster
 
Posts: 620
Default Detecting loss of ADSL & switchover to 3G

Comments in-line

No, the DHCP server recognises the MAC address of your router and issues
the IP address specifed for that MAC address. Unless their DHCP server
is faulty ....


I don't see how it can be doing that since I have two identically
configured 2955s (but their MAC addresses can't be the same) which I
can swap and everything works as before.


You are correct. What I described is how DHCP reservations work on a LAN.

I imagine the IP address is looked up from your account parameters when
the PPP session starts. It really must be a problem at A&A ...

[snip]


I asked them if you could look at their logs to see why the 3G failed
on the 13th.


But that's not what happened, according to your previous explanation.
What you said was that the ADSL got the "wrong" IP address, so your VPN
and RDP connections would not work. So far as A&A was concerned, your
ADSL connection was good, so there was no reason to switch to 3G.

The man refused to do anything about it.


That's worrying. My impression is that A&A are the best ISP for this
class of service.

Clearly if they are not prepared to help, you should ask elsewhere.
Maybe the people here have a recomendation. But LCP monitoring, SMS
messages on failure, and automatic switchover to 3G are not the province
of everyday ISPs.

You could ask Zen if they have a product to meet your needs ...?

Oh yes!

WAN Connection Detection
Mode ARP DetectPing Detect
Ping IP
TTL:

Currenly it is set to ARP detect.

So it looks like I could ping a specific external IP.

What does the TTL parameter do? Is it the number of seconds between
pings?


Google TTL !!!!!!!!!!

If I put in the IP we *should* be getting allocated by the ISP, does
that actually check anything useful? I wonder if it would just do a
local loopback i.e. useless.


If you've been issued the "wrong" IP then somebody else might have been
issued yours. So pinging your IP would not be a useful test. A Cisco
router might allow multiple "beaconing" mechanisms to detect failure.

Ask A&A for one of their internal IP addresses that is only PINGable
from your ADSL connection, but not from elswhere on the internet. They
should at least understand the question!

What do you need from the 2955 that is not provided by the 2830?


I can't recall why we bought it.

SSL VPN perhaps?


[snip]

They have offered a box called a "Firebrick" but I don't want to be
spending yet more of my time (probably days; it usually works out like
that) setting that up. This is supposed to work...

The outage with an IP change is very rare but next time I will make a
note of what it is. It just means I have to go there physically,
because RDP doesn't work.

We have used Clara, Eclipse, and now A&A. All have about the same
downtime rate. Always blamed on BT.


That will always be the case - it is the BT network that provides the
connectivity. But the failover system you have should accommodate this.

Downtime on ZEN has been zero IIRC
over maybe 10 years.


If that's really true you have been very lucky!

--
Graham J


  #10  
Old July 18th 13, 09:12 AM posted to uk.telecom.broadband
The Natural Philosopher
external usenet poster
 
Posts: 2,728
Default Detecting loss of ADSL & switchover to 3G

On 18/07/13 08:00, Peter wrote:
No, the DHCP server recognises the MAC address of your router and issues
the IP address specifed for that MAC address. Unless their DHCP server
is faulty ....

I don't see how it can be doing that since I have two identically
configured 2955s (but their MAC addresses can't be the same) which I
can swap and everything works as before.

radius servers associate login name and IP address if serving 'static'
ip addresses.


--
Ineptocracy

(in-ep-toc'-ra-cy) - a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

 




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
OT - House of Lords inquiry into digital radio switchover DAB sounds worse than FM uk.telecom.broadband (UK broadband) 0 January 27th 10 12:32 PM
Line loss checking prior to adsl Alan uk.telecom.broadband (UK broadband) 3 June 17th 05 01:18 PM
HELP:PC Not Detecting Router - Telewest Joe uk.telecom.broadband (UK broadband) 6 November 12th 03 11:20 AM
HELP:PC Not Detecting Router - Telewest Joe uk.comp.home-networking (UK home networking) 6 November 12th 03 11:20 AM
ADSL Router operating with 62dB loss good? tHatDudeUK uk.comp.home-networking (UK home networking) 8 September 8th 03 12:15 AM


All times are GMT +1. The time now is 05:03 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.Content Relevant URLs by vBSEO 2.4.0
Copyright 2004-2019 BroadbanterBanter.
The comments are property of their posters.