DSLAMs connecting to black holes?

Recently I've been having problems where when my ADSL router connects,
instead of logging in to my ISP, it gets connected to a "black hole"
address such as 172.16.18.48 BLACKHOLE-1.IANA.ORG and the DNS address is
set to a BT one instead of my ISP one. Trying to reconnect a few times
sometimes fixes it, but sometimes the problem persists overnight until it
suddenly goes away about 6am, which suggests someone coming on duty in the
morning and spotting that something is playing up.

Checking the radius logs at my ISP shows there was no attempt to login at
these times, so I assume that the problem must be at the exchange. Can
anyone confirm what would cause such a thing, as my ISP is saying that it
can't be anything to do with them or BT and suggest I check my microfilters
etc. Now it's true I get some crackling on the line at times (and recently
poor speeds, e.g. 1.4 meg instead of the usual 2.5 meg), but could this
really be causing such a screw up during connection? My guess is that BT's
equipment is borked.



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On Wed, 13 Oct 2010 23:54:57 +0000, Gordon Freeman scribe:

> Recently I've been having problems where when my ADSL router connects,
> instead of logging in to my ISP, it gets connected to a "black hole"

Which ISP would this happen to be?

--
You ain't nobody until you do what you want!

In article <Xns9E11950EFBC6C9A7@127.0.0.1>,
Gordon Freeman <(E-Mail Removed)> wrote:
>Recently I've been having problems where when my ADSL router connects,
>instead of logging in to my ISP, it gets connected to a "black hole"
>address such as 172.16.18.48 BLACKHOLE-1.IANA.ORG and the DNS address is
>set to a BT one instead of my ISP one. Trying to reconnect a few times
>sometimes fixes it, but sometimes the problem persists overnight until it
>suddenly goes away about 6am, which suggests someone coming on duty in the
>morning and spotting that something is playing up.

Interesting. I had a similar oddity last weekend - I'm with Zen and
have a /29 network block. To get most flexible use of my IP addresses
I currently run my DSL modem in pppoe bridged mode so that it handles
the ADSL/ATM layer, whilst my gateway Linux machine runs pppd+pppoe for
the IP connectivity.

Just past midnight on the morning of Sat 8th, my pppoe session was
unceremoniously terminated, pppd reporting lack of response from the
remote end. When it tried to reconnect, although login succeeded with
my Zen username, I kept getting a 172.16 address with the nexthop as a
BTInternet gateway. Attempting to use this address didn't work though,
it was indeed a black hole. Like you it fixed itself at about 6am,
so I didn't get a chance to ask Zen what they saw.

However, the DSL layer stayed up throughout, this all seemed to be at
the IP encapsulation level, so I don't know what was going on. I'm a
bit vague on how ADSL/ATM works, were BT routing the ATM VC packets
wrongly somehow ?

Nick
--
Serendipity: http://www.leverton.org/blosxom (last update 29th March 2010)
"The Internet, a sort of ersatz counterfeit of real life"
-- Janet Street-Porter, BBC2, 19th March 1996

Nick Leverton wrote:
> In article <Xns9E11950EFBC6C9A7@127.0.0.1>,
> Gordon Freeman <(E-Mail Removed)> wrote:
>> Recently I've been having problems where when my ADSL router connects,
>> instead of logging in to my ISP, it gets connected to a "black hole"
>> address such as 172.16.18.48 BLACKHOLE-1.IANA.ORG and the DNS address is
>> set to a BT one instead of my ISP one. Trying to reconnect a few times
>> sometimes fixes it, but sometimes the problem persists overnight until it
>> suddenly goes away about 6am, which suggests someone coming on duty in the
>> morning and spotting that something is playing up.
>
> Interesting. I had a similar oddity last weekend - I'm with Zen and
> have a /29 network block. To get most flexible use of my IP addresses
> I currently run my DSL modem in pppoe bridged mode so that it handles
> the ADSL/ATM layer, whilst my gateway Linux machine runs pppd+pppoe for
> the IP connectivity.
>
> Just past midnight on the morning of Sat 8th, my pppoe session was
> unceremoniously terminated, pppd reporting lack of response from the
> remote end. When it tried to reconnect, although login succeeded with
> my Zen username, I kept getting a 172.16 address with the nexthop as a
> BTInternet gateway. Attempting to use this address didn't work though,
> it was indeed a black hole. Like you it fixed itself at about 6am,
> so I didn't get a chance to ask Zen what they saw.
>
> However, the DSL layer stayed up throughout, this all seemed to be at
> the IP encapsulation level, so I don't know what was going on. I'm a
> bit vague on how ADSL/ATM works, were BT routing the ATM VC packets
> wrongly somehow ?
>
> Nick
I think BT are fucking around with their backhaul something shocking at
the moment.

My total loss of connectivity last weekend was a BT backhaul upgrade
apparently. That went a bit pear shaped.