Why can't I listen on 'localhost' but can I listen on '127.0.0.1'?

node.js localhost config webmin virtualmin
pimvdb picture pimvdb · Jul 24, 2011 · Viewed 8.2k times · Source

I'm having difficulties understanding why the following line of code works in node.js:

server.listen(12345, "127.0.0.1"); // works

but this one does not:

server.listen(12345, "localhost"); // fails

Coding localhost literally results in the following error thrown:

events.js:45
        throw arguments[1]; // Unhandled 'error' event
                       ^
Error: ECONNREFUSED, Could not contact DNS servers
    at IOWatcher.callback (dns.js:74:15)

I do not understand why it should 'contact DNS servers' as it's localhost as defined in my HOSTS file (I'm using node.js under Windows).

Why doesn't hardcoding localhost work?

Answer

Andrey Sidorov picture Andrey Sidorov · Jul 24, 2011

Are uou using cygwin build? Did you try 'Set up Domain Name Resolution (DNS)' :

Cygwin internally uses Windows for DNS queries. node.js uses the c-ares library that relies on /etc/resolv.conf. Cygwin ships with an empty /etc/resolv.conf. In order to enabled networking from your scripts, add these IPs to the file (Google Public DNS):

$ vim /etc/resolv.conf

nameserver 8.8.8.8
nameserver 8.8.4.4

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