option --ipv4 kicks IO::Socket::INET6

[doekia]

Despite passing --ipv4 at command line, the code tries to initiate ipv6 socket.

By changing line 409: if ($addr_family == AF_INET6) {

The code works as expected

[mludvig]

Hi, That's interesting, even without your fix it works for me as expected. What mail server are you trying it against and what's your OS and Perl version?

[doekia]

This is perl 5, version 14, subversion 2 (v5.14.2) built for x86_64-linux-gnu-thread-multi Debian 8

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Original code says on line 199: my $socket6 = eval { require IO::Socket::INET6; require Socket6; 1; }; Which set $socket6 to 1 if the library is present and original code line 409: if ($socket6) { $connect_args{'Domain'} = $addr_family; $sock = IO::Socket::INET6->new(%connect_args) or die ("Connect failed: $@\n"); } else { $sock = IO::Socket::INET->new(%connect_args) or die ("Connect failed: $@\n"); } Hence the socket is created using IO::Socket::INET6

[mludvig]

It's using IO::Socket::INET6 but should set address family to IPv4. What behaviour did you observe? Did it make IPv6 connections when --ipv4 was set? Or what was the problem?

[doekia]

The problem was that the IPv6 layer on the host was misconfigured. The socket creation failed.

By forcing the code to create IO::Socket::INET rather than IO::Socket::INET6, I nailed down the root cause of the problem to be at the INET6 layer. And fixed it. To me a flag forcing ipv4 should not try ipv6 even if the ipv6 normally fallback properly.

However, great code I use it from time to time to identify weird issues with mailer.

[mludvig]

I couldn't reproduce it but I guess it's no harm to force using IO::Socket::INET instead of INET6 when --ipv4 is requested. It's in Version 3.9 just released.