ServerSocket / linux iptables problem

[flapcat]

Hello all,

I am attempting to construct a firewall/packet filtering system under linux, and need it to recognise connections to a ServerSocket on a specified port. However, new ServerSockets are not assigned to a specific IP address, as they are always at a port on the local host. Linux iptables will not recognise the request however as there is no IP address.

So I was wondering......

Is there any way of creating a ServerSocket with an IP address?

thanks

[flapcat]

Oops....

Sorry I just found the constructor that allows you to specify an IP address.

This is now linux iptables-specific and I apologise, but if anyone can help it would be much appreciated!

Please move to a more relevant forum if needed.

I have set up iptables to accept inputs to the localhost for packets to/from port 200 by:

iptables -A INPUT -d localhost -p tcp --dport 200 -j ACCEPT
iptables -A INPUT -d localhost -p tcp --sport 200 -j ACCEPT

the default policy is set to DROP.

My Java application attempts to create a new ServerSocket on port 200 with the following:


code:
--------------------------------------------------------------------------------

java.net.InetAddress addr = java.net.InetAddress.getLocalHost(); server = new ServerSocket(200,0,addr);

--------------------------------------------------------------------------------

but the packet doesn't get through. any ideas?

[awoodland]

What are your output and forward default policy's, and do you have any rules in the nat or filter or mangle tables which could be interfering?

Also try using a port > 1024, since iirc on unix/linux systems ports < 1024 require root priviledges to bind to, though if that were the problem I would expect that you would have had an exception thrown when you tried binding to it.

[flapcat]

hiya,

default policies in forward and output are set to accept, with no other rules or chains called.

I tried a higher port number (1050), but to no avail. It seems to be connnecting eventually, after 3 minutes or so. The socket looks as follows:

server = ServerSocket[addr=localhost/127.0.0.1, port=0, localport=1050]

But I don't see why it should take so long.........?