[erlang-questions] reliably figure out hostname

Gustav Simonsson <>
Thu Aug 2 10:40:03 CEST 2012

{ok, LocalHostName} = inet:gethostname().

You get a hostent record back which has the FQDN.

// Gustav Simonsson

Sent from my PC

----- Original Message -----
> From: "Tim Watson" <>
> To: "Tim Watson" <>
> Cc: "erlang-questions Questions" <>
> Sent: Thursday, 2 August, 2012 10:17:32 AM
> Subject: Re: [erlang-questions] reliably figure out hostname
> Any takers for this? I can't be the only person who's had to figure
> this out. The context is a distributed systems testing framework
> that needs to support resolving 'localhost' to a proper host name so
> the framework can become a hidden node and interact with the other
> erlang nodes It is testing against. Having to specify the real host
> name would make configuring the tool across different machines and
> development environments unpleasantly complicated so figuring out
> the right hostname is a boon in terms of keeping the configuration
> overhead down, but doing this for long names nodes is proving highly
> awkward.
> Can anyone suggest a good portable solution?
> On 31 Jul 2012, at 13:43, Tim Watson <  >
> wrote:
> Is there a way to calculate the hostname reliably across platforms in
> Erlang? I have a non-distributed node that I wish to become a
> distributed node. Normally I call net_kernel:start([Name,
> shortnames]) and this is just fine. It also works with [Name,
> longnames] *sometimes and on some systems* - but other times it
> pukes. I've tried looking in the 'domain' or 'search' entries from
> inet:get_rc/0 but these are not always populated, even when dns
> config is clearly in place. I've also tried using
> 'inet_db:get_searchlist/0' but again, sometimes this returns [[]]
> but net_kernel:start([foobar, longnames]) doesn't work, whereas
> doing net_kernel:start([  , longnames]) does.
> Am I missing something incredibly obvious here? *is* there actually a
> simple way of determining what the proper fqdn for the machine
> should be, without breaking out to the os? I had even considered
> doing inet:gethostbyname/1 but again, the search domains entry seems
> to be empty, so I'd assume that -name foobar will work whereas in
> fact, -name foobar @fqdn is required otherwise net_kernel won't
> start.
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