[petsc-users] osx error

[Matthew Knepley]

On Fri, Sep 18, 2020 at 7:46 AM Mark Adams <mfadams at lbl.gov> wrote:

> Oh you did not change my hostname:
>
> 07:37 master *= ~/Codes/petsc$ hostname
> MarksMac-302.local
> 07:41 master *= ~/Codes/petsc$ ping -c 2 MarksMac-302.local
> PING marksmac-302.local (127.0.0.1): 56 data bytes
> Request timeout for icmp_seq 0
>
> --- marksmac-302.local ping statistics ---
> 2 packets transmitted, 0 packets received, 100.0% packet loss
> 07:42 2 master *= ~/Codes/petsc$
>

This does not make sense to me. You have

  127.0.0.1 MarksMac-302.local

in /etc/hosts, but you cannot resolve that name?

  Matt


> BTW, I used to get messages about some network issue and 'changing host
> name to MarksMac-[x+1].local'. That is, the original hostname
> was MarksMac.local, then I got a message about changing
> to MarksMac-1.local, etc. I have not seen these messages for months but
> apparently this process has continued unabated.
>
>
>
>
>
>
>
>
>
> On Thu, Sep 17, 2020 at 11:10 PM Satish Balay via petsc-users <
> petsc-users at mcs.anl.gov> wrote:
>
>> On Thu, 17 Sep 2020, Matthew Knepley wrote:
>>
>> > On Thu, Sep 17, 2020 at 8:33 PM Barry Smith <bsmith at petsc.dev> wrote:
>> >
>> > > > On Sep 17, 2020, at 4:59 PM, Satish Balay via petsc-users <
>> > > petsc-users at mcs.anl.gov> wrote:
>> > > >
>> > > > Here is a fix:
>> > > >
>> > > > echo 127.0.0.1 `hostname` | sudo tee -a /etc/hosts
>> > >
>> > >  Satish,
>> > >
>> > >    I don't think you want to be doing this on a Mac (on anything?) On
>> a
>> > > Mac based on the network configuration etc as it boots up and as
>> networks
>> > > are accessible or not (wi-fi) it determines what hostname should be,
>> one
>> > > should never being hardwiring it to some value.
>> > >
>> >
>> > Satish is just naming the loopback interface. I did this on all my
>> former
>> > Macs.
>>
>>
>> Yes - this doesn't change the hostname. Its just adding an entry for
>> gethostbyname - for current hostname.
>>
>> >>>
>> 127.0.0.1 MarksMac-302.local
>> <<<
>>
>> Sure - its best to not do this when one has a proper IP name [like
>> foo.mcs.anl.gov] - but its useful when one has a hostname like
>> "MarksMac-302.local" -that is not DNS resolvable
>>
>> Even if the machine is moved to a different network with a different name
>> - the current entry won't cause problems [but will need another entry for
>> the new host name - if this new name is also not DNS resolvable]
>>
>> Its likely this file is a generated file on  macos  - so might get reset
>> on reboot - or some network change? [if this is the case - the change won't
>> be permanent]
>>
>>
>> Satish
>>
>

-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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