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From "Kenji Hollis (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DIRMINA-386) SocketSessionConfigImpl: initialize() uses "localhost" to bind InetSocketAddress, should use IP instead
Date Mon, 11 Jun 2007 06:16:26 GMT

    [ https://issues.apache.org/jira/browse/DIRMINA-386?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12503296
] 

Kenji Hollis commented on DIRMINA-386:
--------------------------------------

> Doesn't changing "localhost" to "127.0.0.1" fix the problem? Here's what I am thinking
of...

You would think so, wouldn't you!  But, no.  The reason it doesn't work is because it's expecting
to be able to get a DNS entry for both the connecting and connected IP addresses from what
I can determine.  If it cannot do this, then the system will throw a SocketClosedException,
which renders the socket useless: you cannot perform a socket option check on a socket that
is not connected.  Binding to :1 is effectively the same as creating a ServerSocket with a
port bind on port 0, and letting the ServerSocket choose the interface to bind to.

The official "fallback" functionality will definitely work in this case, however.  Creating
a new Socket() to do the "dirty work" will provide "close enough" options for the program
to use.  If there are any socket options that don't make sense (ie. receive/send buffers are
tiny), these can be overridden using system defaults or letting the programmer choose to do
so.  But providing an ultimate "safety harness" to create a socket with the least acceptable
parameters makes the most sense here, methinks.

Kinda makes you wonder why they handle it differently in Linux...

> SocketSessionConfigImpl: initialize() uses "localhost" to bind InetSocketAddress, should
use IP instead
> -------------------------------------------------------------------------------------------------------
>
>                 Key: DIRMINA-386
>                 URL: https://issues.apache.org/jira/browse/DIRMINA-386
>             Project: MINA
>          Issue Type: Bug
>          Components: Transport
>    Affects Versions: 1.0.3, 1.1.0
>         Environment: JDK 5/6, Linux, Windows, Solaris
>            Reporter: Kenji Hollis
>             Fix For: 1.0.4, 1.1.1
>
>
> The main issue here is if a programmer has decided to override the DNS entries, or run
the MINA software in a firewalled environment (where DNS is firewalled, for instance), MINA
will throw an "Unresolved Host" IO Exception at line 66 of SocketSessionConfigImpl.java. 
This can flat-out be re-created every time by simply overriding the DNS entry on the local
machine to 127.0.0.1 (resolv.conf).
> Because the "initialize()" function simply binds to localhost to retrieve socket configuration
defaults, there is a better way to approach this.  This method has been tested, and is known
to work.
> Instead of binding to localhost, bind to "127.0.0.1" or "0.0.0.0" as the address.  Binding
to 127.0.0.1 will do the exact same thing, effectively, as looking up localhost.  Ultimately,
this will be a FASTER initialization, as it needs to resolve "localhost" to an IP.  By giving
the system an IP address to begin with, we resolve this issue.
> What I did was created a local private static final String called "LOCALHOST_ADDRESS"
in the top area of the class, and set it to 127.0.0.1.  I then modified line 66 to use LOCALHOST_ADDRESS,
as well as line 73 to use LOCALHOST_ADDRESS on the socket.connect.
> At the company I work for, we were able to recreate the issue of the code NOT working,
and the code WORKING.  By modifying the code to use localhost as 127.0.0.1 or 0.0.0.0, we
got around the DNS lookup failure, and MINA fired right up happily.
> I recommend this fix be added in the next release - both major and minor - for MINA.
 The company I work for is doing performance testing with MINA now, and we may be using it
to replace the main socket functionality if all goes well.  I would like to see this fix in
the next milestone release if at all possible.
> If you need a patch file provided, I would be more than happy to give one!

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