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Hi all,

I am a student learning ruby and I am getting an error that I can't
figure out. It works on my teacher's mac, however does not on my laptop.

Windows Vista 64-bit
My ruby version is: 1.9.1p378 (2010-01-10 revision 26273) [i386-mingw32]


Here is what I've tried in cmd

irb

irb(main):002:0> require 'socket'
=> true
irb(main):005:0> TCPSocket.open('0.0.0.0', 888
Errno::EADDRNOTAVAIL: The requested address is not valid in its context.
- conne
ct(2)
from (irb):5:in `initialize'
from (irb):5:in `open'
from (irb):5
from C:/Ruby19/bin/irb:12:in `<main>'

Any help would be appreciated!
--
Posted via http://www.ruby-forum.com/.

On Jun 2, 2010, at 4:08 PM, Ted Pon wrote:

> Hi all,
>
> I am a student learning ruby and I am getting an error that I can't
> figure out. It works on my teacher's mac, however does not on my
> laptop.
>
> Windows Vista 64-bit
> My ruby version is: 1.9.1p378 (2010-01-10 revision 26273) [i386-
> mingw32]
>
>
> Here is what I've tried in cmd
>
> irb
>
> irb(main):002:0> require 'socket'
> => true
> irb(main):005:0> TCPSocket.open('0.0.0.0', 888
> Errno::EADDRNOTAVAIL: The requested address is not valid in its
> context.
> - conne
> ct(2)
> from (irb):5:in `initialize'
> from (irb):5:in `open'
> from (irb):5
> from C:/Ruby19/bin/irb:12:in `<main>'
>
> Any help would be appreciated!
> --
> Posted via http://www.ruby-forum.com/.
>

Is there a server listening at port 8888?

server = TCPServer.new('0.0.0.0', 888

There's some examples in the Programming Ruby book from the Pragmatic
Publishers.

-Rob


Rob Biedenharn
http://agileconsultingllc.com

http://gaslightsoftware.com

Ted Pon wrote:
> irb(main):002:0> require 'socket'
> => true
> irb(main):005:0> TCPSocket.open('0.0.0.0', 888
> Errno::EADDRNOTAVAIL: The requested address is not valid in its context.

Like it says, 0.0.0.0 is not a valid destination IP address. Try
instead:

TCPSocket.open('127.0.0.1', 888
--
Posted via http://www.ruby-forum.com/.

On 6/2/10, Ted Pon <> wrote:
> Hi all,
>
> I am a student learning ruby and I am getting an error that I can't
> figure out. It works on my teacher's mac, however does not on my laptop.
>
> Windows Vista 64-bit
> My ruby version is: 1.9.1p378 (2010-01-10 revision 26273) [i386-mingw32]
>
>
> Here is what I've tried in cmd
>
> irb
>
> irb(main):002:0> require 'socket'
> => true
> irb(main):005:0> TCPSocket.open('0.0.0.0', 888
> Errno::EADDRNOTAVAIL: The requested address is not valid in its context.
> - conne
> ct(2)
> from (irb):5:in `initialize'
> from (irb):5:in `open'
> from (irb):5
> from C:/Ruby19/bin/irb:12:in `<main>'
>
> Any help would be appreciated!

Apparently, 0.0.0.0 is treated as a loopback address on the mac. Apple
got this wrong; that's a broadcast address and should be treated as
the same as 255.255.255.255. 127.0.0.1 is the canonical loopback
address, and that's what you should use for greatest portability.

Caleb Clausen wrote:
> On 6/2/10, Ted Pon <> wrote:
>> Hi all,
>>
>> I am a student learning ruby and I am getting an error that I can't
>> figure out. It works on my teacher's mac, however does not on my laptop.
>>
>> Windows Vista 64-bit
>> My ruby version is: 1.9.1p378 (2010-01-10 revision 26273) [i386-mingw32]
>>
>>
>> Here is what I've tried in cmd
>>
>> irb
>>
>> irb(main):002:0> require 'socket'
>> => true
>> irb(main):005:0> TCPSocket.open('0.0.0.0', 888
>> Errno::EADDRNOTAVAIL: The requested address is not valid in its context.
>> - conne
>> ct(2)
>> from (irb):5:in `initialize'
>> from (irb):5:in `open'
>> from (irb):5
>> from C:/Ruby19/bin/irb:12:in `<main>'
>>
>> Any help would be appreciated!
>
> Apparently, 0.0.0.0 is treated as a loopback address on the mac. Apple
> got this wrong; that's a broadcast address and should be treated as
> the same as 255.255.255.255. 127.0.0.1 is the canonical loopback
> address, and that's what you should use for greatest portability.

IIUC 0.0.0.0 is the default route, not a broadcast addr. If you bind a
tcp server to 0.0.0.0, then you can accept connections from any
interface. I didn't know you could use this on the client side, too.

Brian Candler wrote:
> Ted Pon wrote:
>> irb(main):002:0> require 'socket'
>> => true
>> irb(main):005:0> TCPSocket.open('0.0.0.0', 888
>> Errno::EADDRNOTAVAIL: The requested address is not valid in its context.
>
> Like it says, 0.0.0.0 is not a valid destination IP address. Try
> instead:
>
> TCPSocket.open('127.0.0.1', 888

Dunno why, but ruby on linux seems to let me connect to 0.0.0.0. A
socket bound to 127.0.0.1 does seem to accept this connection.

On Thu, Jun 3, 2010 at 4:08 AM, Ted Pon <> wrote:
> I am a student learning ruby

welcome

> and I am getting an error that I can't
> figure out. It works on my teacher's mac, however does not on my laptop.

teachers are always ready

> Windows Vista 64-bit
> My ruby version is: 1.9.1p378 (2010-01-10 revision 26273) [i386-mingw32]

ok

> Here is what I've tried in cmd
> irb
> irb(main):002:0> require 'socket'
> => true
> irb(main):005:0> TCPSocket.open('0.0.0.0', 888
> Errno::EADDRNOTAVAIL: The requested address is not valid in its context.
> - connect(2)

hint. you need a pair
you are trying to connect as a client to a server ip 0.0.0.0 thru port 8888
you'll need another server running on your host at 0.0.0.0 thru port 8888
note 0.0.0.0 as client and server is only accessible locally, ergo
your client and server will treat you as local 127.0.0.1 (0.0.0.0 is
just a def gw ip wc in this case, will route you to local 127.0.0.1)

eg,

$ script/server -p 8888
=> Booting Mongrel
=> Rails 2.3.8 application starting on http://0.0.0.0:8888
=> Call with -d to detach
=> Ctrl-C to shutdown server


Processing Rails::InfoController#properties (for 127.0.0.1 at
2010-06-03 12:27:51) [GET]
SQL (0.8ms) SELECT name
FROM sqlite_master
WHERE type = 'table' AND NOT name = 'sqlite_sequence'

Completed in 227ms (View: 17, DB: 1) | 200 OK
[http://0.0.0.0/rails/info/properties]

....
> s=TCPSocket.open('0.0.0.0', 888
=> #<TCPSocket:fd 5>
> s.peeraddr
=> ["AF_INET", 8888, "127.0.0.1", "127.0.0.1"]


kind regards -botp

On 03.06.2010 04:31, Joel VanderWerf wrote:
> Caleb Clausen wrote:
>> On 6/2/10, Ted Pon<> wrote:
>>> Hi all,
>>>
>>> I am a student learning ruby and I am getting an error that I can't
>>> figure out. It works on my teacher's mac, however does not on my laptop.
>>>
>>> Windows Vista 64-bit
>>> My ruby version is: 1.9.1p378 (2010-01-10 revision 26273) [i386-mingw32]
>>>
>>>
>>> Here is what I've tried in cmd
>>>
>>> irb
>>>
>>> irb(main):002:0> require 'socket'
>>> => true
>>> irb(main):005:0> TCPSocket.open('0.0.0.0', 888
>>> Errno::EADDRNOTAVAIL: The requested address is not valid in its context.
>>> - conne
>>> ct(2)
>>> from (irb):5:in `initialize'
>>> from (irb):5:in `open'
>>> from (irb):5
>>> from C:/Ruby19/bin/irb:12:in `<main>'
>>>
>>> Any help would be appreciated!
>>
>> Apparently, 0.0.0.0 is treated as a loopback address on the mac. Apple
>> got this wrong; that's a broadcast address and should be treated as
>> the same as 255.255.255.255. 127.0.0.1 is the canonical loopback
>> address, and that's what you should use for greatest portability.
>
> IIUC 0.0.0.0 is the default route, not a broadcast addr. If you bind a
> tcp server to 0.0.0.0, then you can accept connections from any
> interface. I didn't know you could use this on the client side, too.

But you just said that it's the default route, which is something used
by a client. I don't have my Stevenson handy but IIRC the situation is
like this:

1. 0.0.0.0 when used to bind a server socket is a wildcard for "all
interfaces", which means whichever IP is used to address this host the
socket will listen. In contrast if you bind to 127.0.0.1 you can only
connect from the local machine.

irb(main):001:0> srv = TCPServer.new '0.0.0.0', 33445
=> #<TCPServer:0x104f6400>
irb(main):002:0> srv.close
=> nil
irb(main):003:0> srv = TCPServer.open '0.0.0.0', 33445
=> #<TCPServer:0x106d00c8>
irb(main):004:0> srv.close
=> nil

2. 0.0.0.0 cannot be used as a valid address to connect to - you get
EADDRNOTAVAIL as shown above. Broadcast addresses have all bits of the
host part set and consequently typically end in .255:
http://en.wikipedia.org/wiki/Broadcast_address
http://en.wikipedia.org/wiki/Ip_address

I'd say, if this is possible on a Mac then Apple (or BSD) is doing
something weird here and probably not according to the specs.

3. In routing tables it denotes the default route and is used with
netmask 0:
http://en.wikipedia.org/wiki/0.0.0.0

Kind regards

robert


--
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

Robert Klemme wrote:
> 2. 0.0.0.0 cannot be used as a valid address to connect to - you get
> EADDRNOTAVAIL as shown above.

What surprised to me is that you *can* connect to 0.0.0.0. (It's not
surprising that the connection actually goes to 127.0.0.1.)

Try it on linux:

# shell 1

$ ruby -rsocket -ve 'puts TCPServer.open("0.0.0.0", 888.accept.gets'
ruby 1.8.7 (2010-01-10 patchlevel 249) [x86_64-linux]
hello, world
$

# shell 2

$ ruby -rsocket -ve 'TCPSocket.open("0.0.0.0", 888.puts "hello, world"'
ruby 1.8.7 (2010-01-10 patchlevel 249) [x86_64-linux]
$


Also, this shows it's not just a ruby thing:

$ ping 0.0.0.0
PING 0.0.0.0 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.051 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.043 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.038 ms

On Thu, Jun 3, 2010 at 11:56 PM, Joel VanderWerf
<> wrote:
> What surprised to me is that you *can* connect to 0.0.0.0. (It's not
> surprising that the connection actually goes to 127.0.0.1.)

that is ok.
receivefr 0.0.0.0 (aka INADDR_ANY) will work for any addr (cause
that's what it's used for)
sendto 0.0.0.0 will work only for loopback (for obvious reasons

kind regards -botp