I'm working on a little client/server application. The server does not constantly have a socket open. At regular intervals it opens a socket and listens for a request. Thanks to some advice I got here before, I'm using IO::Select so that I don't block on that socket.

My problem now is that occasionally, when the client sends its udp request, the server does not have the socket open, and an ICMP port unreachable message is sent back to the client. The client dies at this point.

What I want to happen is for the client to resend the request. I'll include the code below. 

#!/usr/bin/perl

use IO::Socket;
foreach $request (@ARGV) {
$MAXLEN = 1024;
$PORTNO = 5151;
$TIMEOUT = 5;
#$request = "198.59.115.12:25";
$server_host = "kona.swcp.com";
$sock = IO::Socket::INET->new(Proto => 'udp',
                              PeerPort => $PORTNO,
                              PeerAddr => $server_host)
        or die "Creating socket:  $!\n";
$sock->send($request) or die "send: $!";

eval {
        local $SIG{ALRM} = sub { die "alarm time out" };
        alarm $TIMEOUT;
        $sock->recv($reply, $MAXLEN)  or die "recv: $!";
        alarm 0;
        1;
} or die "recv from $server_host timed out after $TIMEOUT seconds.\n";

print $reply;
sleep 5;
}

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In reply to don't die, retry by Anonymous Monk

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