Blocking port 7 from latency probes...

[Barry Margolin]

In article <37f237fe.512055306 at ounews.ou.edu>,
Jeff Taylor <NjOeSfPfAtM at Mou.edu> wrote:
>Am I the only one that is getting tired of the latency probes to tcp
>port 7 on my dns servers? I have traced it down to DoubleClick.Net
>using the app Global Dispatch from Resonate. I tried explaining my
>objections to both DoubleClick & Resonate, but they fell upon deaf &
>stupid ears. Here is the last e-mail:

Is your objection that they probe at all, or that they use TCP port 7?
I.e. would you be happier if it used ICMP Echo (i.e. ping)?  If yo don't
want them to probe at all, how do you propose they do latency measurements
so that they can redirect you to the closest server?  I suggest you get
used to this general type of thing: besides Global Dispatch, there's also
Distributed Director from Cisco that does similar stuff; it uses TCP port
53, I presume on the assumption that the DNS query is coming from the
site's or ISP's caching nameserver, so this port is likely to be open.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
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