Path: csiph.com!aioe.org!.POSTED.5Avcpu9drOe6MAssky6/+Q.user.gioia.aioe.org!not-for-mail From: =?UTF-8?Q?Arne_Vajh=c3=b8j?= Newsgroups: comp.lang.java.programmer Subject: Re: InetAddress.isReachable() ? Date: Fri, 23 Oct 2020 20:30:51 -0400 Organization: Aioe.org NNTP Server Lines: 51 Message-ID: References: NNTP-Posting-Host: 5Avcpu9drOe6MAssky6/+Q.user.gioia.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Complaints-To: abuse@aioe.org User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.1 Content-Language: en-US X-Notice: Filtered by postfilter v. 0.9.2 Xref: csiph.com comp.lang.java.programmer:39640 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