(OT?) Anyone wanna address my ISP's issues? [CIDR/BGP question]

Kevin Kinsey kdk at daleco.biz
Thu Jun 14 22:17:23 UTC 2007


Elliot Finley wrote:
> On Thu, 14 Jun 2007 14:44:56 -0500, you wrote:

>> Anyone up for further questions?  The .70 --> .69 route on the
>> modem has a metric of "5", but with the .252 mask, shouldn't it
>> be required to be one hop away?
> 
> We really need further information to debug/diagnose this problem.
> I'll give you a diagnosis for two different scenarios.
> 
> #1) you are using private addresses on your LAN and your DSL
> modem/router is NATting for you:

This is the case.
 
> possible problems:
> 
> Your modem/router isn't routing. ( this is more common than it should
> be.  we replace customers' routers because of this problem regularly.)

We RMA'ed it already, it's the second box and same issues. :-(

Do you mean it should be doing NAT, or routing outside (e.g., RIP)?
I assume the latter?
 
> Your ISP has fat fingered a netmask - most likely changing a .252 to a
> .255.

Well, not in the visible DSL modem's config.  Possibly somewhere else?
 
> #2) you are using public addresses on your LAN and your DSL
> modem/router is just routing for you:

<not the case, per above>
 
> possible problems:
> 
> Same possibilities as above with the addition of:
> 
> Your ISP has *not* put the route in for your public block of IPs.

Granted it's "not the case", but:

I was of the opinion that maybe they hadn't for the one
block we're supposed to be in, thus my question re: BGP for
the 68/30 CIDR, but, per your answer, I've no way to know
unless they tell me since the route isn't publicized.
 
> Your ISP *HAS* put the route in for your public block of IPs, but for
> whatever reason, that route isn't propagating through their network.

Obviously I couldn't say about that.

I'm thinking it's still all about routing.  Problem is it's possibly
more complex, since the local Telco has the DSLAM and the ISP is just
"leasing" over the top.  Whenever they get on the phone with each
other, I can only imagine the finger-pointing going on.

AFAIK, the local telco doesn't actually offer DSL from the local
C.O., so it could be as simple, <<read 'difficult' for behemoths
like the local Bell>> as someone actually going in the building and 
plugging some cable into the DSLAM, or punching a couple of buttons
on said machine.  OTOH, it could be a matter of someone with enough
route-foo with either AT&T or the ISP actually doing a lot of 
investigation and configuration.

> Those will be the most likely problems.  I'm betting on your modem
> being faulty.

Well, hopefully not anymore.  Maybe somebody *smart* will take up
my case.  Should I have 'em call you ;-) ??

Thanks (very much! .. once) again,

Kevin Kinsey

PS > Hah!  Substitute "ISP" for "C.I.A." below....
-- 
Finding out what goes on in the C.I.A. is like performing acupuncture
on a rock.
		-- New York Times, Jan. 20, 1981


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