<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><br class=""></div> try <div class=""><br class=""></div><div class=""> /usr/sbin/traceroute `hostname`</div><div class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Sep 18, 2020, at 10:07 AM, Mark Adams <<a href="mailto:mfadams@lbl.gov" class="">mfadams@lbl.gov</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">Let me know if you want anything else.<div class="">Thanks,</div><div class="">Mark</div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Sep 18, 2020 at 11:05 AM Mark Adams <<a href="mailto:mfadams@lbl.gov" class="">mfadams@lbl.gov</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr" class=""><div dir="ltr" class=""><br class=""></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Sep 18, 2020 at 11:04 AM Satish Balay <<a href="mailto:balay@mcs.anl.gov" target="_blank" class="">balay@mcs.anl.gov</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Fri, 18 Sep 2020, Satish Balay via petsc-users wrote:<br class="">
<br class="">
> > >> 07:41 master *= ~/Codes/petsc$ ping -c 2 MarksMac-302.local<br class="">
> > >> PING marksmac-302.local (127.0.0.1): 56 data bytes<br class="">
> <br class="">
> So it is resolving MarksMac-302.local as 127.0.0.1 - but ping is not responding?<br class="">
> <br class="">
> I know some machines don't respond to external ping [and firewalls can block it] but don't really know if they always respond to internal ping or not.<br class="">
> <br class="">
> If some machines don't respond to internal ping - then we can't use ping test in configure [it will create false negatives - as in this case]<br class="">
<br class="">
BTW: To confirm, please try:<br class="">
<br class="">
ping 127.0.0.1<br class=""></blockquote><div class=""><br class=""></div><div class=""><br class=""></div>11:02 master *= ~/Codes/petsc$ sudo vi /etc/hosts<br class="">11:02 master *= ~/Codes/petsc$ ping 127.0.0.1<br class="">PING 127.0.0.1 (127.0.0.1): 56 data bytes<br class="">Request timeout for icmp_seq 0<br class="">Request timeout for icmp_seq 1<br class="">Request timeout for icmp_seq 2<br class="">Request timeout for icmp_seq 3<br class="">Request timeout for icmp_seq 4<br class="">Request timeout for icmp_seq 5<br class="">Request timeout for icmp_seq 6<br class="">Request timeout for icmp_seq 7<br class="">Request timeout for icmp_seq 8<br class="">Request timeout for icmp_seq 9<br class="">Request timeout for icmp_seq 10<br class="">Request timeout for icmp_seq 11<br class="">Request timeout for icmp_seq 12<br class="">Request timeout for icmp_seq 13<br class="">Request timeout for icmp_seq 14<br class="">Request timeout for icmp_seq 15<br class="">Request timeout for icmp_seq 16<br class="">Request timeout for icmp_seq 17<br class="">Request timeout for icmp_seq 18<br class="">Request timeout for icmp_seq 19<br class="">Request timeout for icmp_seq 20<br class=""><div class="">Request timeout for icmp_seq 21</div><div class=""><br class=""></div><div class="">still going ......</div><div class=""> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<br class="">
Satish<br class="">
<br class="">
> <br class="">
> <br class="">
> Mark, can you remove the line that you added to /etc/hosts - i.e:<br class="">
> <br class="">
> 127.0.0.1 MarksMac-302.local<br class="">
> <br class="">
> And now rerun MPI tests. Do they work or fail?<br class="">
> <br class="">
> [this is to check if this test is a false positive on your machine]<br class="">
> <br class="">
> Satish<br class="">
> <br class="">
> <br class="">
> On Fri, 18 Sep 2020, Mark Adams wrote:<br class="">
> <br class="">
> > On Fri, Sep 18, 2020 at 7:51 AM Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank" class="">knepley@gmail.com</a>> wrote:<br class="">
> > <br class="">
> > > On Fri, Sep 18, 2020 at 7:46 AM Mark Adams <<a href="mailto:mfadams@lbl.gov" target="_blank" class="">mfadams@lbl.gov</a>> wrote:<br class="">
> > ><br class="">
> > >> Oh you did not change my hostname:<br class="">
> > >><br class="">
> > >> 07:37 master *= ~/Codes/petsc$ hostname<br class="">
> > >> MarksMac-302.local<br class="">
> > >> 07:41 master *= ~/Codes/petsc$ ping -c 2 MarksMac-302.local<br class="">
> > >> PING marksmac-302.local (127.0.0.1): 56 data bytes<br class="">
> > >> Request timeout for icmp_seq 0<br class="">
> > >><br class="">
> > >> --- marksmac-302.local ping statistics ---<br class="">
> > >> 2 packets transmitted, 0 packets received, 100.0% packet loss<br class="">
> > >> 07:42 2 master *= ~/Codes/petsc$<br class="">
> > >><br class="">
> > ><br class="">
> > > This does not make sense to me. You have<br class="">
> > ><br class="">
> > > 127.0.0.1 MarksMac-302.local<br class="">
> > ><br class="">
> > > in /etc/hosts,<br class="">
> > ><br class="">
> > <br class="">
> > 09:07 ~/.ssh$ cat /etc/hosts<br class="">
> > ##<br class="">
> > # Host Database<br class="">
> > #<br class="">
> > # localhost is used to configure the loopback interface<br class="">
> > # when the system is booting. Do not change this entry.<br class="">
> > ##<br class="">
> > 127.0.0.1 localhost<br class="">
> > 255.255.255.255 broadcasthost<br class="">
> > 127.0.0.1 MarksMac-5.local<br class="">
> > 127.0.0.1 <a href="http://243.124.240.10.in-addr.arpa.private.cam.ac.uk/" rel="noreferrer" target="_blank" class="">243.124.240.10.in-addr.arpa.private.cam.ac.uk</a><br class="">
> > 127.0.0.1 MarksMac-302.local<br class="">
> > 09:07 ~/.ssh$<br class="">
> > <br class="">
> > <br class="">
> > <br class="">
> > <br class="">
> > <br class="">
> > > but you cannot resolve that name?<br class="">
> > ><br class="">
> > > Matt<br class="">
> > ><br class="">
> > ><br class="">
> > >> BTW, I used to get messages about some network issue and 'changing host<br class="">
> > >> name to MarksMac-[x+1].local'. That is, the original hostname<br class="">
> > >> was MarksMac.local, then I got a message about changing<br class="">
> > >> to MarksMac-1.local, etc. I have not seen these messages for months but<br class="">
> > >> apparently this process has continued unabated.<br class="">
> > >><br class="">
> > >><br class="">
> > >><br class="">
> > >><br class="">
> > >><br class="">
> > >><br class="">
> > >><br class="">
> > >><br class="">
> > >><br class="">
> > >> On Thu, Sep 17, 2020 at 11:10 PM Satish Balay via petsc-users <<br class="">
> > >> <a href="mailto:petsc-users@mcs.anl.gov" target="_blank" class="">petsc-users@mcs.anl.gov</a>> wrote:<br class="">
> > >><br class="">
> > >>> On Thu, 17 Sep 2020, Matthew Knepley wrote:<br class="">
> > >>><br class="">
> > >>> > On Thu, Sep 17, 2020 at 8:33 PM Barry Smith <<a href="mailto:bsmith@petsc.dev" target="_blank" class="">bsmith@petsc.dev</a>> wrote:<br class="">
> > >>> ><br class="">
> > >>> > > > On Sep 17, 2020, at 4:59 PM, Satish Balay via petsc-users <<br class="">
> > >>> > > <a href="mailto:petsc-users@mcs.anl.gov" target="_blank" class="">petsc-users@mcs.anl.gov</a>> wrote:<br class="">
> > >>> > > ><br class="">
> > >>> > > > Here is a fix:<br class="">
> > >>> > > ><br class="">
> > >>> > > > echo 127.0.0.1 `hostname` | sudo tee -a /etc/hosts<br class="">
> > >>> > ><br class="">
> > >>> > > Satish,<br class="">
> > >>> > ><br class="">
> > >>> > > I don't think you want to be doing this on a Mac (on anything?)<br class="">
> > >>> On a<br class="">
> > >>> > > Mac based on the network configuration etc as it boots up and as<br class="">
> > >>> networks<br class="">
> > >>> > > are accessible or not (wi-fi) it determines what hostname should be,<br class="">
> > >>> one<br class="">
> > >>> > > should never being hardwiring it to some value.<br class="">
> > >>> > ><br class="">
> > >>> ><br class="">
> > >>> > Satish is just naming the loopback interface. I did this on all my<br class="">
> > >>> former<br class="">
> > >>> > Macs.<br class="">
> > >>><br class="">
> > >>><br class="">
> > >>> Yes - this doesn't change the hostname. Its just adding an entry for<br class="">
> > >>> gethostbyname - for current hostname.<br class="">
> > >>><br class="">
> > >>> >>><br class="">
> > >>> 127.0.0.1 MarksMac-302.local<br class="">
> > >>> <<<<br class="">
> > >>><br class="">
> > >>> Sure - its best to not do this when one has a proper IP name [like<br class="">
> > >>> <a href="http://foo.mcs.anl.gov/" rel="noreferrer" target="_blank" class="">foo.mcs.anl.gov</a>] - but its useful when one has a hostname like<br class="">
> > >>> "MarksMac-302.local" -that is not DNS resolvable<br class="">
> > >>><br class="">
> > >>> Even if the machine is moved to a different network with a different<br class="">
> > >>> name - the current entry won't cause problems [but will need another entry<br class="">
> > >>> for the new host name - if this new name is also not DNS resolvable]<br class="">
> > >>><br class="">
> > >>> Its likely this file is a generated file on macos - so might get reset<br class="">
> > >>> on reboot - or some network change? [if this is the case - the change won't<br class="">
> > >>> be permanent]<br class="">
> > >>><br class="">
> > >>><br class="">
> > >>> Satish<br class="">
> > >>><br class="">
> > >><br class="">
> > ><br class="">
> > > --<br class="">
> > > What most experimenters take for granted before they begin their<br class="">
> > > experiments is infinitely more interesting than any results to which their<br class="">
> > > experiments lead.<br class="">
> > > -- Norbert Wiener<br class="">
> > ><br class="">
> > > <a href="https://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank" class="">https://www.cse.buffalo.edu/~knepley/</a><br class="">
> > > <<a href="http://www.cse.buffalo.edu/~knepley/" rel="noreferrer" target="_blank" class="">http://www.cse.buffalo.edu/~knepley/</a>><br class="">
> > ><br class="">
> > <br class="">
> <br class="">
<br class="">
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