Re: How to check port conection? socket_connect and fsockopen have problems

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BAT, I have tried fsockopen and socket_connect on two machines.
First comp has Kerio firewall, and second hasn't any firewall.
Problem persists on each machine.
And I can't look at remote socket... Comp on other end just doesn't exist...
:)
After timeout (when using fsockopen) SYNC_SENT connection closes normally,
but LISTENING connection remains.

Best regards,
Sherry.


"B.A.T. Svensson" <B.A.T.Svensson@xxxxxxx> ÓÏÏÂÝÉÌ/ÓÏÏÂÝÉÌÁ × ÎÏ×ÏÓÔÑÈ
ÓÌÅÄÕÀÝÅÅ: news:D291F33C586C8E48B95C26F8C805513A01A3DA91@xxxxxxxxxxxxxxxx
> Ok, I see the nature of the problem now.
>
> You probably get all these SYNC_SENT and TIME_WAIT because
> the hand shake is not properly done between the machines.
>
> SYNC_SENT means that the local socket is trying to
> established a connection.
>
> TIME_WAIT indicates that no shutdown is (yet) recived
> from the other end.
>
> (This how is the classical SYNC-attack works, i.e.
> open a port on the remote machine, and drop the
> connection without picking up the SYNC_SENT pakages,
> leaving the remote server port in TIME_WAIT - this way
> one can "eat up" all ports on a remote machine.)
>
> In these cases it very useful to have a look at the socket
> state at the remote peer to determine weather the sync
> package was received or not.
>
>
> Firewalls can sometimes screw up this kind of traffic,
> and drop SYNC packages in both direction without no good
> reason - the firewall log may complain that the package
> "looks like" it was forged, but in fact it is just fine.

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