Java socket “successfully” connect to any IP on port 80












3















I'm trying to open a socket to a remote server, but I want to get an exception thrown if the other side is not responding. For some reason, any IP which I try with PORT 80 seems to "connect" even if it's a completely random IP.



I'll try to convey the issue with an example.



This will timeout and raise an exception:



Socket s = new Socket();
s.connect(new InetSocketAddress("1.2.3.4", 81), SOME_TIMEOUT_CONST);


On the other hand, the following will continue normally as if it connected successfully:



Socket s = new Socket();
s.connect(new InetSocketAddress("1.2.3.4", 80), SOME_TIMEOUT_CONST);


I can't seem to figure out the reason for that.



If this is the expected behavior, how can I check that in case 2 it did not actually connect?



Edit: I ran the same code on a friend's pc, and both cases timed out and raised an exception. So it's probably something with my Mac. No idea what...










share|improve this question

























  • I believe port 80 is used by web servers as a standard, but I'm not knowledgeable in the area; nor do I know if that has any bearing on what you're seeing.

    – Slaw
    Dec 29 '18 at 16:37













  • Interesting. According to this dupe with no accepted answer, it could be your firewall. Also found this on the Oracle forum from 2009 - also unanswered - that blames it on Vista.

    – Johnny Mopp
    Dec 29 '18 at 16:43


















3















I'm trying to open a socket to a remote server, but I want to get an exception thrown if the other side is not responding. For some reason, any IP which I try with PORT 80 seems to "connect" even if it's a completely random IP.



I'll try to convey the issue with an example.



This will timeout and raise an exception:



Socket s = new Socket();
s.connect(new InetSocketAddress("1.2.3.4", 81), SOME_TIMEOUT_CONST);


On the other hand, the following will continue normally as if it connected successfully:



Socket s = new Socket();
s.connect(new InetSocketAddress("1.2.3.4", 80), SOME_TIMEOUT_CONST);


I can't seem to figure out the reason for that.



If this is the expected behavior, how can I check that in case 2 it did not actually connect?



Edit: I ran the same code on a friend's pc, and both cases timed out and raised an exception. So it's probably something with my Mac. No idea what...










share|improve this question

























  • I believe port 80 is used by web servers as a standard, but I'm not knowledgeable in the area; nor do I know if that has any bearing on what you're seeing.

    – Slaw
    Dec 29 '18 at 16:37













  • Interesting. According to this dupe with no accepted answer, it could be your firewall. Also found this on the Oracle forum from 2009 - also unanswered - that blames it on Vista.

    – Johnny Mopp
    Dec 29 '18 at 16:43
















3












3








3


2






I'm trying to open a socket to a remote server, but I want to get an exception thrown if the other side is not responding. For some reason, any IP which I try with PORT 80 seems to "connect" even if it's a completely random IP.



I'll try to convey the issue with an example.



This will timeout and raise an exception:



Socket s = new Socket();
s.connect(new InetSocketAddress("1.2.3.4", 81), SOME_TIMEOUT_CONST);


On the other hand, the following will continue normally as if it connected successfully:



Socket s = new Socket();
s.connect(new InetSocketAddress("1.2.3.4", 80), SOME_TIMEOUT_CONST);


I can't seem to figure out the reason for that.



If this is the expected behavior, how can I check that in case 2 it did not actually connect?



Edit: I ran the same code on a friend's pc, and both cases timed out and raised an exception. So it's probably something with my Mac. No idea what...










share|improve this question
















I'm trying to open a socket to a remote server, but I want to get an exception thrown if the other side is not responding. For some reason, any IP which I try with PORT 80 seems to "connect" even if it's a completely random IP.



I'll try to convey the issue with an example.



This will timeout and raise an exception:



Socket s = new Socket();
s.connect(new InetSocketAddress("1.2.3.4", 81), SOME_TIMEOUT_CONST);


On the other hand, the following will continue normally as if it connected successfully:



Socket s = new Socket();
s.connect(new InetSocketAddress("1.2.3.4", 80), SOME_TIMEOUT_CONST);


I can't seem to figure out the reason for that.



If this is the expected behavior, how can I check that in case 2 it did not actually connect?



Edit: I ran the same code on a friend's pc, and both cases timed out and raised an exception. So it's probably something with my Mac. No idea what...







java sockets






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 30 '18 at 7:07







GuD

















asked Dec 29 '18 at 16:16









GuDGuD

162




162













  • I believe port 80 is used by web servers as a standard, but I'm not knowledgeable in the area; nor do I know if that has any bearing on what you're seeing.

    – Slaw
    Dec 29 '18 at 16:37













  • Interesting. According to this dupe with no accepted answer, it could be your firewall. Also found this on the Oracle forum from 2009 - also unanswered - that blames it on Vista.

    – Johnny Mopp
    Dec 29 '18 at 16:43





















  • I believe port 80 is used by web servers as a standard, but I'm not knowledgeable in the area; nor do I know if that has any bearing on what you're seeing.

    – Slaw
    Dec 29 '18 at 16:37













  • Interesting. According to this dupe with no accepted answer, it could be your firewall. Also found this on the Oracle forum from 2009 - also unanswered - that blames it on Vista.

    – Johnny Mopp
    Dec 29 '18 at 16:43



















I believe port 80 is used by web servers as a standard, but I'm not knowledgeable in the area; nor do I know if that has any bearing on what you're seeing.

– Slaw
Dec 29 '18 at 16:37







I believe port 80 is used by web servers as a standard, but I'm not knowledgeable in the area; nor do I know if that has any bearing on what you're seeing.

– Slaw
Dec 29 '18 at 16:37















Interesting. According to this dupe with no accepted answer, it could be your firewall. Also found this on the Oracle forum from 2009 - also unanswered - that blames it on Vista.

– Johnny Mopp
Dec 29 '18 at 16:43







Interesting. According to this dupe with no accepted answer, it could be your firewall. Also found this on the Oracle forum from 2009 - also unanswered - that blames it on Vista.

– Johnny Mopp
Dec 29 '18 at 16:43














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