[Techtalk] Re: Email Headers

[Mary]

On Fri, Feb 06, 2004, Berenice Chong wrote:
> Thanks. I was poking around last night for a DNS lookup command and
> didn't know it was called "dig" :D  I ended up using traceroute to get
> the domain names but when I tried it for 203.51.210.51, it only
> displayed asterisks (as opposed to yahoo, which didn't - bearing in
> mind that yahoo has a number of addresses) Why do some IP addresses do
> this?

Either because it's unreachable or because one of the routers between you
and it doesn't return traceroute style packets.

traceroute isn't entirely reliable for exactly this reason (some routers
don't allow ping packets either...)

-Mary