Ping Class java
Marc van den Bogaard
Does anyone know a Ping Class in Java
to do a simple "ping" on a server and reading the response?
Didn't find anything usefull up to now.
Thank you in advance!
Skip
news:112807182...@spandrell.news.uk.clara.net...
> Hi all!
>
> Does anyone know a Ping Class in Java
> to do a simple "ping" on a server and reading the response?
>
> Didn't find anything usefull up to now.
In the Sun Runtime there are no APIs that expose this behaviour.
Marc van den Bogaard
In the meantime I found out, that Java doesn't support
Raw Sockets which are necessary to do such a ICMP ECHO (Ping).
But you can use Native C Code.
Calling the native code using the JNI interface.
The finishing touch is to wrap the JNI call in an RMI class.
Thats the theory...
Thomas Fritsch
Since Java 1.5 there is a ping-like method in java.net.InetAddress:
public boolean isReachable(int timeout)
<http://java.sun.com/j2se/1.5.0/docs/api/java/net/InetAddress.html#isReachable(int)>
--
"Thomas:Fritsch$ops:de".replace(':','.').replace('$','@')
Camel
--------------------------------------------------
import java.net.*;
import java.io.*;
import java.util.*;
public class pingTest {
public static void main(String[] args) {
String ip = args[0];
String pingResult = "";
String pingCmd = "ping " + ip;
try {
Runtime r = Runtime.getRuntime();
Process p = r.exec(pingCmd);
BufferedReader in = new BufferedReader(new
InputStreamReader(p.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) {
System.out.println(inputLine);
pingResult += inputLine;
}
in.close();
}//try
catch (IOException e) {
System.out.println(e);
}
}
}
"Marc van den Bogaard" <marc.b...@gmx.de> wrote in message
news:112807182...@spandrell.news.uk.clara.net...
Roedy Green
<marc.b...@gmx.de> wrote or quoted :
>Does anyone know a Ping Class in Java
>to do a simple "ping" on a server and reading the response?
Ping is a very low level protocol not supported by Java. You can get
the same effect probing one of the higher level protocols supported
like HTTP, FTP, SMTP, NTP, NNTP...
More and more servers are ignoring ping probes.
--
Canadian Mind Products, Roedy Green.
http://mindprod.com Again taking new Java programming contracts.
gerr...@yahoo.com
Take a look at the nio examples:
http://java.sun.com/j2se/1.5.0/docs/guide/nio/example/Ping.java
Alan Krueger
> Marc van den Bogaard wrote:
>> Does anyone know a Ping Class in Java
>> to do a simple "ping" on a server and reading the response?
>
> http://java.sun.com/j2se/1.5.0/docs/guide/nio/example/Ping.java
Just to be clear, that doesn't implement an ICMP-based ping (echo
request and response). Instead, it connects to the daytime port (port
13) at the specified host. A declining number of hosts actually support
that service anymore.
steve
(in article <112807182...@spandrell.news.uk.clara.net>):
here ya go.
steve
//this class is for testing the conectivity to a database
//actually it times the connection setup time
//in theory this can be used to find the closest database to the client
location.
//date may-09-2004
package Services;
import java.io.*;
import java.net.*;
public class Pinger {
// byte[] addr1 = new byte[]{(byte)192,(byte)168,(byte)2,(byte)5};
public static long testDBConn(byte[] addr1, int port, int timeoutMs) {
//pass in a byte array with the ipv4 address, the port & the max time
out required
long start = -1; //default check value
long end = -1; //default check value
long total = -1; // default for bad connection
//make an unbound socket
Socket theSock = new Socket();
try {
InetAddress addr = InetAddress.getByAddress(addr1);
SocketAddress sockaddr = new InetSocketAddress(addr, port);
// Create the socket with a timeout
//when a timeout occurs, we will get timout exp.
//also time our connection this gets very close to the real time
start = System.currentTimeMillis();
theSock.connect(sockaddr, timeoutMs);
end = System.currentTimeMillis();
} catch (UnknownHostException e) {
start = -1;
end = -1;
} catch (SocketTimeoutException e) {
start = -1;
end = -1;
} catch (IOException e) {
start = -1;
end = -1;
} finally {
if (theSock != null) {
try {
theSock.close();
} catch (IOException e) {
}
}
if ((start != -1) && (end != -1)) {
total = end - start;
}
}
return total; //returns -1 if timeout
}
}
steve
(in article <112807182...@spandrell.news.uk.clara.net>):
> Hi all!
whoops.
heres a test case
/*
//This is a test class
public static void main(String[] args) {
// byte[] addr1 = new
byte[]{(byte)192,(byte)168,(byte)2,(byte)5};
int port = 1521;
int timeoutMs = 2000; // 2 seconds
long value = testDBConn(addr1, port, timeoutMs);
System.out.println(value);
}
*/
basically , you don't need to implement a "ping" , by using the java classes
correctly, to get a connection reply , you have to make a connection by
opening a socket.
logically if you can open a socket , the server must be connected.
you do not actually have to send any data , just look for a socket
connection.
steve
Guenter Dannhaeuser
[...]
>//this class is for testing the conectivity to a database
>//actually it times the connection setup time
>//in theory this can be used to find the closest database to the client
>location.
> // Create the socket with a timeout
> //when a timeout occurs, we will get timout exp.
> //also time our connection this gets very close to the real time
> start = System.currentTimeMillis();
> theSock.connect(sockaddr, timeoutMs);
> end = System.currentTimeMillis();
> } catch (UnknownHostException e) {
> start = -1;
> end = -1;
> } catch (SocketTimeoutException e) {
> start = -1;
> end = -1;
Hi,
I扉e tried this, but apparently the timeout value is neglected.
Testing a connection to a host using a timeoutMS of 300 resulted in
values (end-start) > 4000 in that case. No SocketTemoutException
raised. Tested with JDK1.5.0_03 and _05. Any ideas?
Thanks,
guenter <gd--acm-org>
Roedy Green
wrote or quoted :
>I´ve tried this, but apparently the timeout value is neglected.
There was another post recently complaining timeouts were being
ignored.
Maybe that number is really just a suggested MINIMUM timeout and the
actual can be much longer.
Perhaps the problem is in the OS.
Is anyone aware of experiments on this?
steve
(in article <rsv1l1to669m2p021...@4ax.com>):
> On Sat, 8 Oct 2005 13:59:00 +0800, steve <st...@aol.com> wrote:
> [...]
>> //this class is for testing the conectivity to a database
>> //actually it times the connection setup time
>> //in theory this can be used to find the closest database to the client
>> location.
> [...]
>> // Create the socket with a timeout
>> //when a timeout occurs, we will get timout exp.
>> //also time our connection this gets very close to the real time
>> start = System.currentTimeMillis();
>> theSock.connect(sockaddr, timeoutMs);
>> end = System.currentTimeMillis();
>> } catch (UnknownHostException e) {
>> start = -1;
>> end = -1;
>> } catch (SocketTimeoutException e) {
>> start = -1;
>> end = -1;
> [...]
>
> Hi,
>
> I´ve tried this, but apparently the timeout value is neglected.
> Testing a connection to a host using a timeoutMS of 300 resulted in
> values (end-start) > 4000 in that case. No SocketTemoutException
> raised. Tested with JDK1.5.0_03 and _05. Any ideas?
>
> Thanks,
> guenter <gd--acm-org>
how odd!!
it was cut directly from a working file.
and it is working perfectly on macs and on windows se, but then again we are
on 1.4.2.
I know it works , because i use it to decide between 2 different databases,
for clients internally and externally to the network.
it takes 5 reading , for 192.168.2.9, XXX.XXX.XXX.XXX, YYY.YYY.YYY.YYY,
then averages out the connection times.
XXX.XXX.XXX.XXX, YYY.YYY.YYY.YYY, are in different parts of the world.
if you are connected internally it connects to : 192.168.2.9
if you are external it makes a connection to either : XXX.XXX.XXX.XXX,
YYY.YYY.YYY.YYY depending on the lowest latency.
it checks 192.168.2.9, first so if it was not timing out in less than 4
seconds , the client would get stuck , for 20 seconds ( 5 readings of 4
seconds).
I just tested it for a local database i got 11ms
for no database i got -1
that was using
//This is a test class
public static void main(String[] args) {
// byte[] addr1 = new
byte[]{(byte)192,(byte)168,(byte)2,(byte)5};
int port = 1521;
int timeoutMs = 2000; // 2 seconds
long value = testDBConn(addr1, port, timeoutMs);
System.out.println(value);
}
then i tested a database that i know drops some packets:, all this was in
less than 3 seconds.
Debugger connected to local process.
Deadlock detection is not supported by the debuggee virtual machine.
31
13
14
-1
15
15
15
15
15
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15
-1
16
-1
15
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-1
16
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65
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67
33
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17
64
16
15
15
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15
15
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31
16
16
15
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15
16
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15
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15
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15
-1
27
17
15
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15
16
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16
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58
15
19
16
16
16
17
16
17
Debuggee process paused.
Guenter Dannhaeuser
Ok, some more testing done, I now think the problem is not the timeout
being ignored, but the time for executing the connect: doing something
like
[...]
Socket theSock = new Socket();
start0 = System.currentTimeMillis();
theSock.connect(sockaddr, timeoutMs);
end0 = System.currentTimeMillis();
theSock = new Socket();
start1 = System.currentTimeMillis();
theSock.connect(sockaddr, timeoutMs);
end1 = System.currentTimeMillis();
[...]
sometimes returns big values (>4000ms) for (end0 - start0) and usually
values in the expected range for (end1 - start1). Is this a problem of
JIT-Compiling?
However, looking at
http://java.sun.com/j2se/1.5.0/docs/guide/nio/example/Ping.java
I扉e managed to get a solution that愀 working for me atm, based on a
thread observing finishConnect() on a SocketChannel.
Please excuse any bad coding style (it愀 my first week on java ;) -
remarks very welcome.
-- 8< -------------------------------------------------------------
package myping;
import java.io.*;
import java.net.*;
import java.nio.channels.*;
public class Ping {
private static int timeout; // Timeout in ms for pinging
private static Target t;
private static SocketChannel sc;
// Representation of a ping target
private static class Target {
public InetSocketAddress address;
public SocketChannel channel;
public long connectStart;
public long connectFinish = 0;
public Exception failure = null;
public Target(String host, int port) throws IOException {
address = new
InetSocketAddress(InetAddress.getByName(host), port);
}
public long getPing() throws IOException, InterruptedException
{
if (connectFinish != 0)
return connectFinish - connectStart;
else if (failure != null)
if (failure instanceof IOException)
throw (IOException) failure;
else if (failure instanceof InterruptedException)
throw (InterruptedException) failure;
else
return -2; //should not happen
else
return -1; //Timed out
}
}
// Thread for connecting to target
private static class connector extends Thread {
private volatile boolean shutdown = false;
public connector() {
setName("connector");
}
public void shutdown() {
shutdown = true;
}
public void run() {
for (;;) {
if (shutdown) {
return;
}
// Attempt to complete the connection sequence
try {
if (sc.finishConnect()) {
t.connectFinish = System.currentTimeMillis();
sc.close();
return;
}
} catch (IOException x) {
try {
sc.close();
} catch (IOException xx) {
t.failure = xx;
}
t.failure = x;
}
}
}
}
public static long ping(String host, int port, int timeout) throws
InterruptedException, IOException {
Ping.t = new Target(host, port);
Ping.timeout = timeout;
// Initiate a connection sequence to the given target
Ping.sc = null;
// Open the channel, set it to non-blocking, initiate connect
sc = SocketChannel.open();
sc.configureBlocking(false);
sc.connect(t.address);
// Record the time we started
t.connectStart = System.currentTimeMillis();
t.channel = sc;
connector conn = new connector();
conn.start();
conn.join(timeout);
conn.shutdown();
sc.close();
return t.getPing();
}
public static void main(String[] args) throws
InterruptedException, IOException {
System.out.println(ping("123.123.123.123", 7, 500)); //host,
port, timeout in ms
}
}
-- 8< -------------------------------------------------------------
cheers,
guenter. <gd--acm-org>
Roedy Green
<see.ms...@invalid.de> wrote or quoted :
> start1 = System.currentTimeMillis();
> theSock.connect(sockaddr, timeoutMs);
> end1 = System.currentTimeMillis();
You never showed us your code for displaying end1-start1. You may
have muddled the values before displaying them.
E.J. Pitt
Err, 'A typical implementation will use ICMP ECHO REQUESTs if the
privilege can be obtained, otherwise it will try to establish a TCP
connection on port 7 (Echo) of the destination host.'
Guenter Dannhaeuser
>You never showed us your code for displaying end1-start1. You may
>have muddled the values before displaying them.
Ok, I扉e surrounded the measurement in steve愀 class with a for-loop
and output it directly:
-- 8< ----------------------------------------------------------------
import java.io.*;
import java.net.*;
public class Pinger {
// byte[] addr1 = new
byte[]{(byte)192,(byte)168,(byte)2,(byte)5};
public static long testConn(byte[] addr1, int port, int timeoutMs)
{
//pass in a byte array with the ipv4 address, the port & the
max time out required
long start = -1; //default check value
long end = -1; //default check value
long total = -1; // default for bad connection
//make an unbound socket
Socket theSock = null;
try {
InetAddress addr = InetAddress.getByAddress(addr1);
SocketAddress sockaddr = new InetSocketAddress(addr,
port);
// Create the socket with a timeout
//when a timeout occurs, we will get timout exp.
//also time our connection this gets very close to the
real time
for (int i = 0; i < 10; i++) {
theSock = new Socket();
start = System.currentTimeMillis();
theSock.connect(sockaddr, timeoutMs);
end = System.currentTimeMillis();
System.out.println(end - start);
}
} catch (UnknownHostException e) {
start = -1;
end = -1;
} catch (SocketTimeoutException e) {
start = -1;
end = -1;
} catch (IOException e) {
start = -1;
end = -1;
} finally {
if (theSock != null) {
try {
theSock.close();
} catch (IOException e) {
}
}
if ((start != -1) && (end != -1)) {
total = end - start;
}
}
return total; //returns -1 if timeout
}
public static void main(String[] args) {
byte[] addr = new
byte[]{(byte)123,(byte)123,(byte)123,(byte)123};
int port = 123;
int timeout = 500;
for (int i = 0; i < 2; i++) {
System.out.println(Pinger.testConn(addr, port, timeout));
}
}
}
-- 8< ----------------------------------------------------------------
Output for this always is something like
-- 8< ----------------------------------------------------------------
4802
282
281
282
266
282
281
282
281
282
282
4771
282
281
282
297
282
297
266
281
282
282
-- 8< ----------------------------------------------------------------
greets,
guenter. <gd--acm-org>
steve
(in article <vje4l11uuh4oiiglr...@4ax.com>):
> On Sun, 16 Oct 2005 04:15:40 GMT, Roedy Green wrote:
>
>> You never showed us your code for displaying end1-start1. You may
>> have muddled the values before displaying them.
>
> Ok, I´ve surrounded the measurement in steve´s class with a for-loop
how odd!!.
I'm normally very careful before releasing code, to ensure it is good.
I currently have this running over several hundred clients, with the results
back-ended to an oracle database, and have not seen this.
Perhaps it is actually correct-!!, and you seeing , either something in the
jvm or you are seeing some real latency in the network for some reason.
I have just run it over 7 different hosts in our network, from both inside
and outside the net. and i cannot duplicate your problem.
the only thing i see is the -1.
but to get a result of 4771, 4802 ,would indicate the timer is not firing
in 500ms, which would indicate a possible jvm bug,(or a service tie up,
which would still be a bug)
perhaps you need to pass the code to sun along with details of your setup.
the code differs in that it is actually a service finder, as opposed to a
real ping, in was using it for looking for services.
and originally i also passed in the port numbers.
try adding a for next delay of about 1 second , between calls, it might be a
function of your firewall. trying to stop a DOS attack ( currently the code
runs as fast as it can open a port, which with a single ip address looks very
much like a DOS)
maybe we can get others in the group to run the code to see what their
results are?
Anyway This is from a client outside our company to our server, i''ll not
bore you with 7 outputs
actual ping from my system.
64 bytes from 59.37.49.52: icmp_seq=0 ttl=58 time=11.966 ms
64 bytes from 59.37.49.52: icmp_seq=1 ttl=58 time=11.721 ms
64 bytes from 59.37.49.52: icmp_seq=2 ttl=58 time=11.959 ms
64 bytes from 59.37.49.52: icmp_seq=3 ttl=58 time=11.968 ms
64 bytes from 59.37.49.52: icmp_seq=4 ttl=58 time=23.224 ms
64 bytes from 59.37.49.52: icmp_seq=5 ttl=58 time=15.842 ms
64 bytes from 59.37.49.52: icmp_seq=6 ttl=58 time=22.223 ms
64 bytes from 59.37.49.52: icmp_seq=7 ttl=58 time=44.964 ms
64 bytes from 59.37.49.52: icmp_seq=8 ttl=58 time=11.691 ms
64 bytes from 59.37.49.52: icmp_seq=9 ttl=58 time=11.458 ms
64 bytes from 59.37.49.52: icmp_seq=10 ttl=58 time=12.414 ms
64 bytes from 59.37.49.52: icmp_seq=11 ttl=58 time=11.668 ms
64 bytes from 59.37.49.52: icmp_seq=12 ttl=58 time=11.675 ms
64 bytes from 59.37.49.52: icmp_seq=13 ttl=58 time=18.756 ms
64 bytes from 59.37.49.52: icmp_seq=14 ttl=58 time=13.318 ms
64 bytes from 59.37.49.52: icmp_seq=15 ttl=58 time=12.168 ms
64 bytes from 59.37.49.52: icmp_seq=16 ttl=58 time=11.939 ms
64 bytes from 59.37.49.52: icmp_seq=17 ttl=58 time=25.141 ms
64 bytes from 59.37.49.52: icmp_seq=18 ttl=58 time=12.409 ms
64 bytes from 59.37.49.52: icmp_seq=19 ttl=58 time=11.442 ms
64 bytes from 59.37.49.52: icmp_seq=20 ttl=58 time=23.186 ms
64 bytes from 59.37.49.52: icmp_seq=21 ttl=58 time=11.643 ms
64 bytes from 59.37.49.52: icmp_seq=22 ttl=58 time=12.131 ms
64 bytes from 59.37.49.52: icmp_seq=23 ttl=58 time=21.207 ms
64 bytes from 59.37.49.52: icmp_seq=24 ttl=58 time=22.406 ms
64 bytes from 59.37.49.52: icmp_seq=25 ttl=58 time=15.277 ms
64 bytes from 59.37.49.52: icmp_seq=26 ttl=58 time=20.682 ms
from the java thingy jvm 1.4.2_09
12
40
15
15
16
15
19
16
59
27
15
16
67
15
16
16
15
63
26
17
15
18
59
15
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15
16
34
15
24
20
16
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61
15
15
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76
27
17
17
58
15
16
15
15
67
20
16
16
64
15
16
15
15
37
-1
62
17
16
15
16
-1
15
15
60
20
17
16
-1
20
16
68
62
16
18
16
18
16
15
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33
16
15
15
16
40
53
15
15
15
15
58
15
16
-1
16
16
-1
16
15
16
14
16
47
17
16
15
28
15
64
68
33
16
16
30
16
15
68
21
24
28
17
17
15
26
18
66
16
16
22
17
61
19
16
16
44
34
15
25
16
47
17
15
15
16
16
63
16
15
22
16
58
16
16
15
16
64
-1
23
15
16
16
17
19
67
58
17
15
15
15
16
15
16
16
76
58
16
55
13
17
65
73
19
15
15
15
17
15
15
16
-1
16
44
34
15
15
14
15
70
13
18
48
14
16
16
16
16
41
16
23
26
21
66
15
15
16
38
-1
15
59
15
15
15
15
68
14
15
16
15
60
15
16
14
17
72
18
15
18
66
15
15
16
16
68
18
15
15
15
37
Alan Krueger
You should probably cite what you're quoting. In any event, as I
stated, the sample at the URL above does not use TCP port 7, it uses TCP
port 13, the 'daytime' service which seems rarely supported anymore.
A better implementation using the 'echo' service might use UDP instead,
since it doesn't require a connection to be established.
E.J. Pitt
> You should probably cite what you're quoting.
Sorry, I'm quoting the Javadoc for InetAddress.isReachable(), which is
what I thought we were talking about. It wasn't, but it should have been ;-)
Guenter Dannhaeuser
On Wed, 19 Oct 2005 06:04:12 +0800, steve <st...@aol.com> wrote:
>Perhaps it is actually correct-!!, and you seeing , either something in the
>jvm or you are seeing some real latency in the network for some reason.
>but to get a result of 4771, 4802 ,would indicate the timer is not firing
>in 500ms, which would indicate a possible jvm bug,(or a service tie up,
>which would still be a bug)
> perhaps you need to pass the code to sun along with details of your setup.
Hi Steve,
problem found: the JVM is running on Windows XP with netbios over
TCP/IP activated. On connect() the JVM tries to resolve the hostname
(java.net.InetAddress.getHostFromNameService, getHostByAddr).
Windows tries a netbios ns query on udp port 137 with a timeout of
1500ms, ignores any ICMP "port unreachable" packages and repeats this
two more times, adding up to a value of 4.5 seconds (!).
Deactivating netbios "fixes" this, but isn´t always an option ... any
ideas very welcome.
Greets,
guenter <gd--acm-org>
steve
(in article <1t9bl1tpoh9j6qdkl...@4ax.com>):
psodo code!!
if(total> timeoutMs){total=-1; // were on windows?
}
> Greets,
> guenter <gd--acm-org>
Jez, so do we file this under?:
1 a java bug.
2. a windows bug.
3. every other computer in the world is wrong.
That basically must mean that when windows is in it's internal routines that
take too long, that the timeouts for the java ports are being
'missed/overlooked/swallowed', it also accounts for why it's not showing up
on my windows SE . (nitbios is OFF)
Anyway, way to go !!!, on the bug hunt, did you get a packet sniffer on it,
how did you find it?
we could charge for this stuff. ( this is REAL WORLD programming) ;-)
( maybe roedy can get this on his web site)
personally if i were you, I would get a bug filed with sun, or add a fix into
the code so that if the ping reply is > the preset timeout value , you
ignore it, and re-ping.
me, I'm scrapping off all the windows stuff in our office and moving to linux
Steve
Guenter Dannhaeuser
On Wed, 19 Oct 2005 18:45:17 +0800, steve <st...@aol.com> wrote:
>Jez, so do we file this under?:
>1 a java bug.
>2. a windows bug.
>3. every other computer in the world is wrong.
>
>That basically must mean that when windows is in it's internal routines that
>take too long, that the timeouts for the java ports are being
>'missed/overlooked/swallowed', it also accounts for why it's not showing up
>on my windows SE . (nitbios is OFF)
>
>Anyway, way to go !!!, on the bug hunt, did you get a packet sniffer on it,
>how did you find it?
>
>we could charge for this stuff. ( this is REAL WORLD programming) ;-)
> ( maybe roedy can get this on his web site)
>
>personally if i were you, I would get a bug filed with sun, or add a fix into
>the code so that if the ping reply is > the preset timeout value , you
>ignore it, and re-ping.
>
>me, I'm scrapping off all the windows stuff in our office and moving to linux
>Steve
>
Wondering why my gateway showed activity on udp 137, I used a Packet
Analyzer (Packetyzer) on this.
Turning Netbios off: no netbios name resolution, saving 4.5s.
But still Packetyzer showed reverse-ptr DNS lookups, causing
testConn() to return values > timeoutMs ... huh?
These are triggered in the ProxySelector checking wether SOCKS should
be used or not. Disabling proxy support with
ProxySelector.setDefault(null);
or, when creating the socket, with
Socket theSock = new Socket(Proxy.NO_PROXY);
prevents these lookups, passing the calls directly to the plain socket
implementation, resulting in correct timeouts.
Alternatively, using
InetAddress addr = InetAddress.getByAddress(String host, byte[]
addr);
e.g. with
InetAddress addr = InetAddress.getByAddress(ipHost,
IPAddressUtil.textToNumericFormatV4(ipHost));
where ipHost is a String in IP-Format instead of
InetAddress addr = InetAddress.getByAddress(String host);
bypasses reverse lookups and also validity checking on the host
string.
After all, I think I惻l stick to this, it愀 still more elegant and
simpler than the solution with the thread observing connectFinish() on
a SocketChannel I posted in e4b3l15cjaifadjup...@4ax.com
Just been on bugs.java.com:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5092063
describing these problems got closed with state "fixed". So this is
not a bug at all ;) It愀 just bad luck and two days lost.
guenter.
Alan Krueger
> problem found: the JVM is running on Windows XP with netbios over
> TCP/IP activated. On connect() the JVM tries to resolve the hostname
> (java.net.InetAddress.getHostFromNameService, getHostByAddr).
>
> Windows tries a netbios ns query on udp port 137 with a timeout of
> 1500ms, ignores any ICMP "port unreachable" packages and repeats this
> two more times, adding up to a value of 4.5 seconds (!).
>
> Deactivating netbios "fixes" this, but isn´t always an option ... any
> ideas very welcome.
You could try adding that hostname with address to
%SYSTEM%\drivers\etc\hosts
and see if that speeds up your name lookup.
Roedy Green
quoted :
>> problem found: the JVM is running on Windows XP with netbios over
>> TCP/IP activated. On connect() the JVM tries to resolve the hostname
>> (java.net.InetAddress.getHostFromNameService, getHostByAddr).
>>
>> Windows tries a netbios ns query on udp port 137 with a timeout of
>> 1500ms, ignores any ICMP "port unreachable" packages and repeats this
>> two more times, adding up to a value of 4.5 seconds (!).
I have documented this at http://mindprod.com/jgloss/socket.html
The practical solution I would imagine is to put such hosts in your
HOSTS file and maintain them with TweakDUN to ensure the lookup is
fast.
see http://mindprod.com/jgloss/hosts.html
Guenter Dannhaeuser
>The practical solution I would imagine is to put such hosts in your
>HOSTS file and maintain them with TweakDUN to ensure the lookup is
>fast.
Alan Krueger just also suggested this in OiC5f.488$E17...@fe03.lga ,
I´ll reply here:
Problem is, that I do not know a priori which hosts I´m going to ping.
I gather these from parsing a (quite big) list of ips indicating
gateways that should work, but I have to test (some of) them to get a
collection of working ones. I´d have my application to constantly
update the lmhosts-file - not an option.
Anyway, bypassing the ProxySelector-Code (see
g8ccl1lcqgn0g4g2l...@4ax.com) works for me.
greets, guenter. <gd--acm-org>
steve
(in article <g8ccl1lcqgn0g4g2l...@4ax.com>):
> After all, I think I´ll stick to this, it´s still more elegant and
> simpler than the solution with the thread observing connectFinish() on
> a SocketChannel I posted in e4b3l15cjaifadjup...@4ax.com
>
> Just been on bugs.java.com:
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5092063
> describing these problems got closed with state "fixed". So this is
> not a bug at all ;) It´s just bad luck and two days lost.
>
> guenter.
2 days lost , well now you know you are a real programmer ;-)
i've done this before.
Steve
steve
(in article <tc2el1hlel4hac5ei...@4ax.com>):
> On Wed, 19 Oct 2005 18:45:17 +0800, steve <st...@aol.com> wrote or
> quoted :
>
>>> problem found: the JVM is running on Windows XP with netbios over
>>> TCP/IP activated. On connect() the JVM tries to resolve the hostname
>>> (java.net.InetAddress.getHostFromNameService, getHostByAddr).
>>>
>>> Windows tries a netbios ns query on udp port 137 with a timeout of
>>> 1500ms, ignores any ICMP "port unreachable" packages and repeats this
>>> two more times, adding up to a value of 4.5 seconds (!).
>
> I have documented this at http://mindprod.com/jgloss/socket.html
>
> The practical solution I would imagine is to put such hosts in your
> HOSTS file and maintain them with TweakDUN to ensure the lookup is
> fast.
>
> see http://mindprod.com/jgloss/hosts.html
>
you missed throwing windows away as a possible solution ;-)
steve
Roedy Green
quoted :
>you missed throwing windows away as a possible solution ;-)
The boss will say: "The customer is using windows. That's where the
big market is. That's where we have to develop first. It does not
matter what shit it is. Make it work by hook or by crook."
steve
(in article <2qpml1t1s9emman8i...@4ax.com>):
> On Sat, 22 Oct 2005 18:01:26 +0800, steve <st...@aol.com> wrote or
> quoted :
>
>> you missed throwing windows away as a possible solution ;-)
>
> The boss will say: "The customer is using windows. That's where the
> big market is. That's where we have to develop first. It does not
> matter what shit it is. Make it work by hook or by crook."
>
>
>
good job I do all my development on osx.
Then emulate the P.C with Virtual-PC, which incidentally crashes a way lot
less than a real P.C.
to be honest I have lost count of the number of winblows computers I have
smashed up, normally i just do the Keyboard.
Steve