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Standard User lexden16
(member) Sat 08-Mar-14 10:08:25
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CHAP Failure


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I replaced a router on Thursday evening and immediately lost my FTTC connection due to a CHAP failure. Diagnosis was complicated by the fact that when I rang my ISP, I had a PPPoE connection directly to my laptop from the OR modem. When I put the router back in the loop, the CHAP failure re-appeared. Three routers later and a direct re-connect to my laptop and it was obvious that there was an issue. The ISP set 'wheels in motion' and I left the router connected. I had two brief spells of connection at 5 and 9pm last night, and then at 1am my connection was restored - albeit, my speeds have taken a hammering. Of interest, my Max DSLAM throughput is now showing 80/17 rather than the 80/20. I am not sure why. Any thoughts?
Administrator MrSaffron
(staff) Sat 08-Mar-14 12:01:05
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Re: CHAP Failure


[re: lexden16] [link to this post]
 
If the PC can connect reliably with the same credentials then the suggestion is that the settings in the router are suspect.

Which router are you trying to use, and does the old router still work?

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User lexden16
(member) Sat 08-Mar-14 13:03:33
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Re: CHAP Failure


[re: MrSaffron] [link to this post]
 
I have spoken to Zen and they have tested the line and confirmed that the 80/17 is correct and that it is purely the result of the machinations of the DLM. I am still surprised by this given the log stats below:

Negotiated connection properties
Receive Direction Send Direction
Max. DSLAM throughput kbit/s 80000 17000
Min. DSLAM throughput kbit/s 40000 8000
Attainable data rate kbit/s 101320 26662
Current throughput kbit/s 64211 17000
Seamless rate adaptation off off

Latency 7 ms 6 ms
Impulse Noise Protection 4 3
G.inp off off

Signal-to-noise ratio dB 11 9
Bitswap on on
Line attenuation dB 12 0

Profile 17a
G.Vector off off

Carrier record A43 A43

I think that it is clear that the CHAP problem sat somewhere within BT's systems. I was misled initially by the successfull PPPoE connection to a laptop which led Zen to suggest, quite rightly, that the problem was at my end. I tried my old router, an Airport Express and the new router with and without the OR modem and was getting nowhere. It was only after I tried PPPoE direct connectivity to a laptop again and it failed to get a connection that Zen asked me to test with different usernames etc. At this point, they raised a fault with BT.

I am using a new Fritz!Box 7490 in place of a 7390 in VDSL modem mode. Max attainable downstream rate has risen from 93 to 101.3Mbps, and wifi coverage (a separate chip) is considerably stronger. I will update this post when DLM does its thing. My connection has now been steady for 12 hours so hopefully the fault has been resolved.

I now need to sell my 'old' 7390 which comes with 2 years remaining on the original 5 year warranty. Suggestions welcome on how best to sell it!


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Standard User lexden16
(member) Thu 13-Mar-14 11:27:45
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Re: CHAP Failure


[re: lexden16] [link to this post]
 
My connection remained steady for 5 days on a 64/17 profile (but showing 64/20 on BT Speedtest). Just to make sure that the original problem had gone away, I carried out a system reboot. Again I got DSL synch but no authentication. Checked with direct PPPoE to laptop and no authentication. Put everything back together again and it took a hour or so for the handshake to take place. ISP now says that 'they want to try an alternative approach and book a lift and shift'. I am concerned that the engineer will check and say 'NFF' and that I will be on the hook for an SFI charge. I have reverted my VDSL modem/router back to PPPoE mode with a WAN connection to the OR modem. This is what my log says:

3.03.14 10:11:17 Filter list of the web sites banned by the BPjM has been updated successfully.
13.03.14 10:08:24 Internet connection established successfully. IP address: xx.xx.xx.xx, DNS server: 212.23.6.100 and 212.23.3.100, Gateway: 62.3.84.17, Broadband PoP: bras-red1.bm-th-B20C4110500113
13.03.14 10:07:24 Log in with Internet service provider failed. CHAP authentication failure, unit 20178
13.03.14 10:06:23 Log in with Internet service provider failed. CHAP authentication failure, unit 20358
13.03.14 10:05:23 Log in with Internet service provider failed. CHAP authentication failure, unit 18418
13.03.14 10:04:50 PPPoE error: Timeout.
13.03.14 10:04:36 PPPoE error: Timeout.
13.03.14 10:04:22 PPPoE error: Timeout.
13.03.14 10:04:09 PPPoE error: Timeout.
13.03.14 10:03:55 PPPoE error: Timeout.
13.03.14 10:03:42 PPPoE error: Timeout.
13.03.14 10:03:28 PPPoE error: Timeout.
13.03.14 10:03:15 PPPoE error: Timeout.
13.03.14 10:03:01 PPPoE error: Timeout.
13.03.14 10:02:47 PPPoE error: Timeout.
13.03.14 10:02:34 PPPoE error: Timeout.
13.03.14 10:02:20 PPPoE error: Timeout.
13.03.14 10:02:02 Internet connection cleared.

I have kept print outs of these logs but is there anything more that I can do to fend off a pass through charge?
Administrator MrSaffron
(staff) Thu 13-Mar-14 12:32:36
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Re: CHAP Failure


[re: lexden16] [link to this post]
 
PPPoE while ages old still sometimes has bugs and thus it may be the router that has a timeout that is quicker than what BT Wholesale or Zen have in their system.

Without access to the BT Wholesale logs and Zen logs showing what they saw at the same precise time it is difficult to say where the issue may be.

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User lexden16
(member) Thu 13-Mar-14 13:19:59
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Re: CHAP Failure


[re: MrSaffron] [link to this post]
 
I am not worried about the PPPoE. That's ocurring as a result of me switching from VDSL modem/router to OR modem- router bridged mode. The issue is the repeated CHAPs authentication issue. My only concern is that the BT man comes, line tests OK and I am on the hook for £200+. I am just trying to minimise this risk.
Administrator MrSaffron
(staff) Thu 13-Mar-14 13:30:46
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Re: CHAP Failure


[re: lexden16] [link to this post]
 
My bet is on the engineer finding nothing wrong with the VDSL component

CHAP issues are all part of the authentication process and either its CPE or something in the network, or worse everyone thinks they've got the code right, but a timeout is set slightly different to the norm and messing things up.

Where the system works sometimes, then short timeouts are most likely issue.

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User lexden16
(member) Fri 14-Mar-14 16:53:13
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Re: CHAP Failure


[re: MrSaffron] [link to this post]
 
I have cancelled the engineer's visit as my ISP is now suggesting that the onus is on me to prove that there is a fault. I am not sure what more I can do. I have ruled out all of my three routers by going for direct PPPoE connection to the BT Modem. I have had some advice from a SFI engineer on another site and I am going to try disconnecting the modem for 24 hours.
Standard User mixt
(experienced) Fri 14-Mar-14 18:29:42
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Re: CHAP Failure


[re: lexden16] [link to this post]
 
This might sound like a bit of a crazy question, but each time you hooked up a new device to the modem to connect through it (be that your laptop or one of the 3 routers etc), did you power cycle the modem on each device swap?

Now on <aaisp.net> (21CN+IPv6+40Mb/FTTC)
Previous ISPs: Virgin Media (50Mb/Cable), Be* Un Limited, ZeN
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Standard User lexden16
(member) Fri 14-Mar-14 19:35:01
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Re: CHAP Failure


[re: mixt] [link to this post]
 
Not every time but yes when I switched modems (ie, F!B , BT modem). DSL synch is achieved in the normal time, the problem is the last part of the loop to the ISP. Two Fritz!Box VDSL and one OR modem cannot all have the same fault. I have also moved the OR modem from the end of the data extension kit to the test socket and failed to make a PPPoE connection with a laptop.
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