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ctrl-c doesn't reliably kill ping
- From: Frank Farance <frank at farance dot com>
- To: cygwin at cygwin dot com
- Date: Mon, 14 Mar 2016 20:45:50 -0400
- Subject: ctrl-c doesn't reliably kill ping
- Authentication-results: sourceware.org; auth=none
- References: <56E6F25A dot 7070000 at gmx dot de>
I have been having this problem with "ping". If I "ping" a location that
doesn't exist, then "ping" just hangs and cannot be killed via "kill -KILL [pid]".
A little digression, so you understand the background ... The workstation I am
doing this from is connected to a Verizon router to their FIOS network. Now the
reason I mention this is that the router's DNS (via DHCP to my workstation) is
192.168.1.1, which I presume is forwarded from the router upstream to Verizon's
DNS caches. So if I type the URL http://something.that.doesnt.exist in my
browser, rather than getting a Hostname Not Found error (at the name resolution
level), it actually loads up a page saying "something.that.doesnt.exist" isn't
found and then I have a Yahoo set of search results on things matching the
So all of this is normal ISP stuff: they actually resolve unknown addresses to
their own website (which is 220.127.116.11).
Ok, ending the digression ....
Back to the problem, so when I type
$ ping some.unknown.host
according to "ping", the hostname resolves to 18.104.22.168 (as per the
explanation above), but I cannot kill "ping". I tried "ping" with a limited
packet size and count so, in theory, "ping" would die on its own after 10
packets, such as:
$ ping some.unknown.host 50 10
but it still hangs rather than timing out. If I ping to some actual IP address
that is unresponsive (route-able to the last subnet, but dies on the floor at
the end), then I can kill via ctrl-c. My only solution to the hanging "ping" is
to kill the terminal window.
Any suggestions on:
- Why "ping" behaves this way?
- How to avoid this problem?
Thanks, in advance.
Frank Farance, Farance Inc. T: +1 212 486 4700 M: +1 917 751 2900
Standards/Products/Services for Information/Communication Technologies
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