Groups > comp.lang.java.programmer > #39645

Re: InetAddress.isReachable() ?

From	Martin Gregorie <martin@mydomain.invalid>
Newsgroups	comp.lang.java.programmer
Subject	Re: InetAddress.isReachable() ?
Date	2020-10-29 21:36 +0000
Organization	A noiseless patient Spider
Message-ID	<rnfck3$pdq$1@dont-email.me> (permalink)
References	(2 earlier) <rmvnsi$1dn$1@dont-email.me> <rmvsjs$1h20$1@gioia.aioe.org> <rmvt2a$nt2$1@dont-email.me> <rn144s$bq6$1@dont-email.me> <rnf8co$5ph$1@dont-email.me>

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On Thu, 29 Oct 2020 15:23:51 -0500, Knute Johnson wrote:

> Sorry to be slow responding Martin.  It's been one of those weeks.
>
No problem - been there too. Thanks for the fuller explanation.

Of course you can't ask a client to run Wireshark, but it probably 
wouldn't help with the problem anyway, now that I understand the setup.

However, if you know the problem client's URL or IP or can get then to 
tell you what it is, then there's nothing to stop you pinging them or 
using traceroute to see if the problem was transient or permanent and 
where it is. 

Whether you get a response from ping will depend on how their cable/ADSL/
whatever modem and firewall is configured. Mine, for example, is 
configured to give no response whatsoever on any channel to stop the bad 
lads from thinking there's anything turned on at my site (and checked for 
invisibility against Gibson Labs).

However, traceroute should do its thing no matter what state how the 
client 's front door is configured. because it will and either reach the 
client's endpoint and say so, or, if it can't reach that, show you where 
the failure is.

I hope this is useful info.

-- 
--  
Martin    | martin at
Gregorie  | gregorie dot org

Thread

InetAddress.isReachable() ? Knute Johnson <knute2020@585ranch.com> - 2020-10-23 11:50 -0500
  Re: InetAddress.isReachable() ? Arne Vajhøj <arne@vajhoej.dk> - 2020-10-23 13:14 -0400
    Re: InetAddress.isReachable() ? Knute Johnson <knute2020@585ranch.com> - 2020-10-23 18:10 -0500
      Re: InetAddress.isReachable() ? Arne Vajhøj <arne@vajhoej.dk> - 2020-10-23 20:30 -0400
        Re: InetAddress.isReachable() ? Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2020-10-23 19:38 -0500
          Re: InetAddress.isReachable() ? Martin Gregorie <martin@mydomain.invalid> - 2020-10-24 11:45 +0000
            Re: InetAddress.isReachable() ? Knute Johnson <nospam@rabbitbrush.frazmtn.com> - 2020-10-29 15:23 -0500
              Re: InetAddress.isReachable() ? Martin Gregorie <martin@mydomain.invalid> - 2020-10-29 21:36 +0000
              Re: InetAddress.isReachable() ? Arne Vajhøj <arne@vajhoej.dk> - 2020-10-29 21:47 -0400
                Re: InetAddress.isReachable() ? Knute Johnson <knute2020@585ranch.com> - 2020-11-01 10:30 -0600

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