Path: csiph.com!eternal-september.org!feeder.eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail From: Knute Johnson Newsgroups: comp.lang.java.programmer Subject: Re: InetAddress.isReachable() ? Date: Fri, 23 Oct 2020 19:38:34 -0500 Organization: A noiseless patient Spider Lines: 58 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Sat, 24 Oct 2020 00:38:34 -0000 (UTC) Injection-Info: reader02.eternal-september.org; posting-host="8eb32e87f926618d8a7168e49e8ae1fc"; logging-data="24482"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+eBZmNFM3B8snTGMlhufq9" User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 Cancel-Lock: sha1:Zcj9LUtVf48TJFDuWJAw3G3l44I= In-Reply-To: Content-Language: en-US Xref: csiph.com comp.lang.java.programmer:39641 On 10/23/2020 19:30, Arne Vajhøj wrote: > On 10/23/2020 7:10 PM, Knute Johnson wrote: >> On 10/23/20 12:14 PM, Arne Vajhøj wrote: >>> On 10/23/2020 12:50 PM, Knute Johnson wrote: >>>> InetAddress.isReachable() only works if I run Java as root.  Any >>>> idea how to make it work with a regular user?  The docs say "A >>>> typical implementation will use ICMP ECHO REQUESTs if the privilege >>>> can be obtained".  I'm assuming that's why it won't work as a >>>> regular user. >>> >>> Is it worth it? >> >> Yes > > OK. > >>> The method can return false and the service you want to use >>> can be available (firewall blocking ICMP and Echo but not application >>> protocol). >> >> No firewalls there. >> >>> The method can return true and the service you want to use >>> can be unavailable (OS running but server application down). >> >> No service to connect to.  Just want to see if there is a path to the >> router. >> >>> I think you would be better of connecting to the service >>> you want to use and handle errors there. >> >> Again no service to connect to. >> >> It's an internal network and I'm fielding calls all the time that 'we >> aren't getting updates to our data'.  If I can ask is the little box >> green or red I'll know with some certainty the status of their network >> connection.  I'm 1600 km from the site so I can't just pop over for a >> look see.  I can't ask them to ping the router, that's a step too far. >> The network service at the remote sites is interrupted on a fairly >> regular basis. >> >> So yes I would really like to figure out how to make this work is it >> is possible. > > I cannot believe there are any ways to get around the privilege issue. > > If there were then it would be a bug that would be fixed. > > That leaves you with the awful hack of running the external > ping command and read output. > > Arne > That's what I was afraid of Arne. Oh well, I didn't have anything else to do this week :-).