Sending ICMP packet:

Generally you can't. If you talk about ping, try:

/* pseudo code */

runTime.exec("ping");

hiwaa at 2007-7-29 12:33:48 >

> IIRC the isReachable() method in InetAddress uses

> icmp if possible, but falls back on udp or so.

I've had horrible luck with that. I've never been able to be able to get it to return true for anything other than localhost, even when ping works fine.

jverda at 2007-7-29 12:33:48 >

> IIRC the isReachable() method in InetAddress uses

> icmp if possible, but falls back on udp or so.

No. That was the plan, but the WINSOCK API doesn't support it properly, and you need root privilege on Unix, so end of plan. It just uses TCP to port 7.

But pings are usually a complete waste of time. If you want to know whether a host is up, just try connecting to the server you want to connect to. Then you (a) know the host is up, (b) know the server is up, and (c) have a usable connection. The ping only does a third of that, even if you could do it, and there would still a timing-window problem and the possibility that the server isn't listening.

ejpa at 2007-7-29 12:33:48 >

> The problem is that i want to send some data using

> ICMP Packets.

> I used UDP packets but they are blocked by firewall.

> So i need to send the very small code using ICMP

> packet. Earlier we used vc++ and we did it, but now

> we have shifted application to java and i want the

> same to work in java.

>

> Is it really impossible? if so then what

> should i do...

Native code. You have a C/C++ library that does it? Write JNI to that

georgemca at 2007-7-29 12:33:48 >

> So, you want to say that there is no way to do that

> in Java...

I don't want to, but I don't really have a choice. My hands are tied by reality I'm afraid

georgemca at 2007-7-29 12:33:48 >

> http://www.koders.com/java/fid93EB3022C6BCB6EAC082BE8C

> B13E925DB2F0266B.aspx?s=icmp

>

> I think that uses JNI for Win32 (HWAddr etc)

>

> yup

> http://www.koders.com/c/fid4304E1C9A704965DAFAE6504718

> A83BC193287D3.aspx

>

> Message was edited by:

> jGardner

http://www.koders.com/java/fid7EF10E94485F17CEAF71A8FE68A205DB3470A25C.aspx?s=icmp

Has some native methods in it

edit: interesting. I was in the process of replying to your post, and although I'd already quoted your pre-edit post, Jive was smart enough to quote the edited version

Message was edited by:

georgemc

georgemca at 2007-7-29 12:33:48 >

> i don't think so...

You don't think what?

georgemca at 2007-7-29 12:33:48 >

I am too tired to deal with sockets this early in the morning; that package looks like it might be of use.

All I can tell you is this: if you are going to use JNI to do it, and you are using windows, do not write it yourself; Winsock has the most ridiculously stupid API with the possible exception of the windows.h GUI API. Your eyes will hemorrhage.

jGardnera at 2007-7-29 12:33:53 >

> yes i understand that we have to use something other

> than java to do the real task.

And JGardener gave a good pointer to something that will help. Also, in a previous post you said you'd done this before in VC++, so if you've got that dll kicking about, you could re-use that and write a bit of JNI for it

georgemca at 2007-7-29 12:33:53 >

> The problem is that i want to send some data using

> ICMP Packets.

Why would you want to do that?

> I used UDP packets but they are blocked by firewall.

> So i need to send the very small code using ICMP

> packet. Earlier we used vc++ and we did it, but now

> we have shifted application to java and i want the

> same to work in java.

Many firewall configurations block ping too. The fact that yours doesn't seem to do so now, doesn't mean it won't later on, and consequently break your app.

Again, what is it that you want to accomplish?

As mentioned, there are better ways to check for a live machine/server in Java accross firewalls, using simply HTTP.

karma-9a at 2007-7-29 12:33:53 >

I don't think he quite understands what ICMP is designed to do...

http://www.koders.com/info.aspx?c=ProjectInfo&pid=5B5A1PCAKW68H26USWFR9ZHQSH

I'll be damned. I wonder if the native code is on a low enough level where it wont even matter what platform you did it on? they have hardware drivers there too

http://www.koders.com/java/fidA592B0378941A9D1A1A3F3C8BDEF280CEFBF504B.aspx

jGardnera at 2007-7-29 12:33:53 >

Is this a flow in java that we cannot create and send ICMP packets in java.

Nistelrooya at 2007-7-29 12:33:53 >

> > Is this a flow in java that we cannot create and

> send

> > ICMP packets in java.

>

> Not a flaw. It just doesn't do it. ICMP isn't really

> designed to carry application data, using it to get

> through a firewall is a bit hacky

QFT.

Nistel: http://www.ietf.org/rfc/rfc0792.txt

Chances are it is going to downright ignore anything that isn't defined there.

jGardnera at 2007-7-29 12:33:53 >

> i am not talking about sending application data. i

> want to sent a password. It can be sent as

> simultaneous ICMP Packets after one second and can be

> decoded at the other end... something like this i

> think...

Chances are it will just give you back ICMP 12.

jGardnera at 2007-7-29 12:33:53 >

can i use INetAddress Class. I think it send ICMP packets when checking the isReacheable() method

Nistelrooya at 2007-7-29 12:33:53 >

we can send that in parts i think the the real problem is how to send.

Nistelrooya at 2007-7-29 12:33:59 >

because the target server's firewall does not allow any other protocol than ICMP

Nistelrooya at 2007-7-29 12:33:59 >

> because the target server's firewall does not allow

> any other protocol than ICMP

Then if that server is to be involved in something that does require another protocol, the firewall needs to be altered. There are other ways to secure data than simply blocking as many protocols as you can get away with. You have a genuine business case for TCP/IP to be opened up here

georgemca at 2007-7-29 12:33:59 >

> because the target server's firewall does not allow

> any other protocol than ICMP

I find it strange that a secure server will allow ICMP traffic, and not HTTP/HTTPS.

AFAIK, there are much more security issues with allowing ICMP traffic due to the implications of raw sockets access (variants of the Ping of Death, smurf attacks, etc..)

karma-9a at 2007-7-29 12:33:59 >

I agree with u all but i the problem is that i still have to send ICMP packets, i cannot change the whole network because it is not mine and nor can i change the process, i have to do my job and that is to send ICMP packets and that is why i am asking for help.

Nistelrooya at 2007-7-29 12:33:59 >

But the facts of that aside you really, really, really, really, really need to get a better handle on your requirements because they are also bogus.

cotton.ma at 2007-7-29 12:33:59 >

> Than what the hell is this:

>

> public class PortUnreachableException

> extends SocketException

>

> Signals that an ICMP Port Unreachable message has

> been received on a connected datagram.

>

> Well, if java.net has a exception for ICMP,

That exception is not encountered by your using ICMP (as the documentation makes VERY clear) it is possibly encountered when you are using UDP.

> I can

> supose that i can have something for ICMP using Java

Yes, you are right, we are all lying to you. You can use ICMP in Java by using the java.net.icmp package.

Good luck!

cotton.ma at 2007-7-29 12:33:59 >

Very tiresome.

To the OP: it is time to stop floundering around and do some research.

(a) Java does not let you send ICMP in any way shape or form.

(b) ICMP doesn't let you write application or authentication data, from any language.

(c) No server can exist, practically speaking, that only speaks ICMP.

(d) The assertion that the server does authentication by ICMP is therefore 100% grade A nonsense.

What is the basis for this belief? What you are saying, and/or what you have been asked to do, is truly impossible.

Find someone who knows the system and actually knows that they are talking about.

ejpa at 2007-7-29 12:34:05 >

> if u do not know any thing than don't try to be

> oversmart

The problem is not us being overly smart, the problem is that you are overly dumb. Try and see if you can get that fixed somehow.

And there is only person in this thread who "do not know any thing" and that is "u".

cotton.ma at 2007-7-29 12:34:05 >

i am not being rude... if i am trying to explain something that i want to do....

i know it is a bit different but it is not impractical...

Nistelrooya at 2007-7-29 12:34:05 >

Yes, i understand...

ok thanks everyone for your help and time... i think i have to find some native api and use that...

Nistelrooya at 2007-7-29 12:34:05 >

why so... if i could use the native api and call that using JNI... won't it work

Nistelrooya at 2007-7-29 12:34:05 >

> why so... if i could use the native api and call that

> using JNI... won't it work

No, it won't.

JNI was a suggestion for PING functionality, as was Runtime.exec with the ping or fping command.

PING uses ICMP, but only as echo packets. You want to send data (passw) using ICMP. That's a whole different story.

I am sorry to say, but nor your requirements, nor your description of your environment make any sense.

karma-9a at 2007-7-29 12:34:05 >

> I agree with u all but i the problem is that i still

> have to send ICMP packets, i cannot change the whole

> network because it is not mine and nor can i change

> the process, i have to do my job and that is to send

> ICMP packets and that is why i am asking for help.

It is your duty - as part of this job - to inform the client that it cannot be done, then. No, I am not joking, and yes, that is exactly what I would do in your situation

georgemca at 2007-7-29 12:34:05 >

> i am not being rude... if i am trying to explain

> something that i want to do....

> i know it is a bit different but it is not

> impractical...

You are being rude, and somewhat foolish. Any idea how tiresome it is to be told repeatedly that your factual information is unacceptable? It's flattering in a way that you think an utterance from one of us will change reality, but it won't

Not impractical, no. Just impossible

georgemca at 2007-7-29 12:34:05 >

> if u do not know any thing than don't try to be

> oversmart

Stop being a flaming pigfucking *******.

You have been given the facts. You have chosen to ignore them and whine about what you want, as if whining enough will change the facts.

Kindly go away and never come back.

jverda at 2007-7-29 12:34:10 >

prob sol!

more or less anyway.

cotton.ma at 2007-7-29 12:34:10 >

> >Stop being a flaming pigfucking *******.

>

> I am not doing that but i think u are...

>

> >You have been given the facts. You have chosen to

> ignore them and whine about what >you want, as if

> whining enough will change the facts.

>

> i was just asking if anyone else knows.

Which is basically you saying you don't believe anyone else in this thread. Which is quite insulting, really

georgemca at 2007-7-29 12:34:10 >

> i don't know why are u trying to expand the whole

> matter.

To underline the point that being insulting toward people who don't give you acceptable answers won't change the fact that certain things just can't be done. Last year, there was a guy asking how to use Java to control the temp. of his CPU. When I told him it couldn't be done, he started following me to other threads telling the posters that I was disparaging and rude, and not to listen to me. As such, I take exception to posters who refuse to accept the answers they've asked for, just because they don't like them

If you don't want to continue with this, you don't have to

georgemca at 2007-7-29 12:34:10 >