You can use the ProxyCommand feature of OpenSSH (requires tunnels enabled on host b and a relatively recent version of OpenSSH on the local host): 
my $ssh_b = Net::OpenSSH->new($host_b, ...);
$ssh_b->error and die;
my $tunnel_cmd = $ssh_b->make_remote_command({tunnel => 1}, $host_c, 2
+2);
my $ssh_c = Net::OpenSSH->new($host_c, master_opts => [-o => "ProxyCom
+mand=$tunnel_cmd"], ...);
$ssh_c->error and die;
$ssh_c->system('ls');

[download]
Another option is to install Net::OpenSSH::Gateway available from GitHub. 
my $ssh_c = Net::OpenSSH->new($host_c, gateway => { proxy => "ssh://$h
+ost_b"}, ...);

[download]
That module implements a set of strategies to forward SSH connections over different kinds of proxies including SSH gateways. It is not on CPAN because I was not happy with its internal architecture and planed to revamp it completely but unfortunately, I never got the time (or the guts) to actually do it and it has languished there. In any case I would fix any bug reported.

In reply to Re: openssh start another ssh session on machine b by salva
in thread openssh start another ssh session on machine b by jhuijsing

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.