problem specifying port to ssh
Daniel Kahn Gillmor
dkg-openssh.com at fifthhorseman.net
Fri Apr 7 13:15:10 EST 2006
On April 6, don-temp28 at isis.cs3-inc.com said:
> Daniel Kahn Gillmor writes:
>
> > nisplus relies on a NIS+ server being present (and configured). If
> > your workstation is looking for NIS+ information from a host that is
> > not providing it, it probably will fail.
> In which case a well behaved glibc would go on to use the next method
> in the list. So I think this is a bug.
i agree: it sounds like this could potentially be a bug in your
nisplus nss module, for example.
> This still doesn't explain why ssh -p 22 should be any different
> from ssh without -p at all. I'd expect the same underlying call
> to one of the functions above, and I would expect the attempt to
> resolve the host name to not depend on the port at all.
huh. this is odd. from what Darren Tucker said:
> > > The port number is passed to getaddrinfo() along with the
> > > hostname. It would appear that your system can handle hostname
> > > alone, but isn't happy with both.
i'd expected that if you didn't supply the port, openssh would just
call getaddrinfo("isis.cs3-inc.com", NULL, ...) and then set
aitop->ai_addr->sin_port to 22 explicitly.
but (at least on my debian etch/sid system here) reviewing
ssh_connect() (in sshconnect.c [0]) shows that's not the case, and you're
right that it does appear to be the same call to getaddrinfo:
[dkg at squeak ~]$ ltrace -e getaddrinfo ssh fubar
getaddrinfo("fubar", "22", 0xbfe30c00, 0xbfe30c64) = -2
ssh: fubar: Name or service not known
+++ exited (status 255) +++
[dkg at squeak ~]$ ltrace -e getaddrinfo ssh -p 22 fubar
getaddrinfo("fubar", "22", 0xbfd765f0, 0xbfd76654) = -2
ssh: fubar: Name or service not known
+++ exited (status 255) +++
[dkg at squeak ~]$ ssh -V
OpenSSH_4.2p1 Debian-8.dkg1, OpenSSL 0.9.8a 11 Oct 2005
[dkg at squeak ~]$
What does your FC4 version of openssh-4.2p1 do with this library call?
--dkg
[0] http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshconnect.c?rev=1.180&content-type=text/x-cvsweb-markup
More information about the openssh-unix-dev
mailing list