Hi,

I'm trying to write an SSL proxy using IO::Socket::SSL::Intercept in order to do DNS based inspection of traffic to a specific host, and it's mostly working except I'm seeing strange intermittent failures when trying to connect to the real SSL server on behalf of the client. Here is the relevant code: 

    # SSL connect to server
    my $retry = 10;
    my $server = undef;
    while ($retry > 0) {
        $server = IO::Socket::SSL->new(
            PeerAddr    => $host,
            PeerPort    => "https",
        );
        if ($server && $server->connected()) {
            print "proxy $$ connected to server\n";
            last;
        } else {
            $retry--;
            warn "proxy $$ connect to server failed: $!,".IO::Socket::
+SSL::errstr();
            warn "proxy $$ ".($retry ? 'will retry' : 'giving up')."\n
+";
        }
    }

[download]
And here is a typical result. Sometimes it will work the first time, sometimes it has to retry a few times: 
proxy 4730 connect to server failed: Interrupted system call,SSL wants
+ a read first at ./proxy line 110.
proxy 4730 will retry
proxy 4730 connected to server

[download]
I'm not seeing this against all hosts, which leads me to believe that there may be something strange going on at the far end, but I'd rather have some input from people who have done this sort of thing before I start pointing fingers. 

# uname -a
Linux redacted 4.6.0-kali1-amd64 #1 SMP Debian 4.6.4-1kali1 (2016-07-2
+1) x86_64 GNU/Linux

This is perl 5, version 22, subversion 2 (v5.22.2) built for x86_64-li
+nux-gnu-thread-multi
IO::Socket::SSL    2.037
Net::SSLeay 1.77

[download]
Interestingly, IO::Socket::SSL debugging seems to indicate it is 'ignoring' this as a 'less severe local error' but in fact the connection fails: 
DEBUG: .../IO/Socket/SSL.pm:753: done Net::SSLeay::connect -> -1
DEBUG: .../IO/Socket/SSL.pm:763: ssl handshake in progress
DEBUG: ...5.22/IO/Socket.pm:48: ignoring less severe local error 'IO::
+Socket::IP configuration failed', keep 'SSL wants a read first'
DEBUG: .../IO/Socket/SSL.pm:2777: free ctx 44390832 open=44390832 4401
+1664 43990720
DEBUG: .../IO/Socket/SSL.pm:2782: free ctx 44390832 callback
DEBUG: .../IO/Socket/SSL.pm:2789: OK free ctx 44390832
proxy 4824 connect to server failed: Interrupted system call,SSL wants
+ a read first at ./proxy line 110.

[download]
Any thoughts on how to fix this?

-- FloydATC

I got 99 problems, most of them have to do with printers.

In reply to IO::Socket::SSL sometimes says 'SSL wants a read first' by FloydATC

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