Re: major DNS hiccup

Per Hedeland wrote:
In article <X6Oug.14695$EK1.11536@xxxxxxxxxxxxxxxxxxxx> Mike Scott
<usenet.10@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> writes:
Out of curiosity, I tried traceroute -p 53 to one of the root nameservers. The hypothesis was that if ntl have put some sort of transparent cache into place, this /ought/ not to reach the root server - maybe!

That won't work - traceroute always uses multiple ports (increments by
one for each probe), -p just gives the "base" one. I.e. by the time the
probes reach the "interesting" place, the port won't be 53 anymore.

Yes, thanks; I figured that out the hard way after posting (maybe I should start reading man pages :-) ).

And I didn't know that it uses the remote port number to encode the attempt identification, icmp replies apparently not including enough data to match them to the particular sent packets. So it's not quite straightforward to send DNS probes in the same way. I'll keep it on the back burner - if ntl are intercepting DNS packets, there has to be a way to prove it!

....
But I really don't think that your ISP would deny that they are doing
some sort of "intercept" of the DNS traffic (assuming that you can get

The front line support have already denied any network changes affecting DNS. I've no idea at all how to get things like this escalated - front line seems to take the view that rebooting cures almost everything, otherwise they call an engineer to come and look at the modem :-) The very concept of networking problems seems foreign to them.

Thanks again for your help, and of course to the others who've put time into this!

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