(2) rsh and rcp problems between Solaris and FreeBSD
John Von Essen
essenz at bjork.quonix.net
Wed Dec 31 07:21:20 PST 2003
One more thing. Apparently, if I do 'rsh -n host cmd' on the Solaris box,
it no longer hangs, and I can do it back to back indefinitely. Say I do
ten of them, 5 secs apart. I still see the following 10 times in netstat:
tcp4 0 0 mx100.841 embryo.bluebell..1014
TIME_WAIT
After 30 secs they go away.
On Solaris 2.6, the -n to rsh is:
-n Redirect the input of rsh to /dev/null. You
sometimes need this option to avoid unfor-
tunate interactions between rsh and the shell
which invokes it. For example, if you are
running rsh and invoke a rsh in the back-
ground without redirecting its input away
from the terminal, it will block even if no
reads are posted by the remote command. The
-n option will prevent this.
This doesn't affect rcp, so those are still slow. The only other thing is
that I am going through a firewall, from an internal network to a dmz.
-John
On Wed, 31 Dec 2003, Matthew Seaman wrote:
> On Tue, Dec 30, 2003 at 11:42:41PM -0500, John Von Essen wrote:
> >
> > I have a Solaris 2.6 box that has been sending data to a Solaris 8 box
> > via rsh and rcp.
> >
> > I finally changed the Solaris 8 box to a FreeBSD 4.9-STABLE machine.
> >
> > Unfortunately, I am noticing alot of problems with my rsh and rcp
> > calls. Again, the rsh/rcp calls are being initiated on my Solaris 2.6
> > and are hitting a FreeBSD 4.9-STABLE box.
> >
> > Here is what happens:
> >
> > My first rsh works, but if I try another rsh within a few seconds it
> > takes a really long time (30 - 60 sec) to return - but it does return
> > successful. If I issue my rsh calls every 2 minutes, it returns quick
> > everytime. But if I do rsh calls to close together (5 sec delays) they
> > hang for a long time.
>
> Now that is weird. 30-60 second delay sounds like classic DNS
> breakage, but in that case you'ld see it the first time you connected
> and probably subsequent times.
>
> How are you doing name resolution on this system -- host files, NIS,
> DNS, something else? Are you using Kerberos at all? Does toggling
> the use of the '-D' and '-n' flags in inetd.conf on the FreeBSD side
> make any difference?
>
> Hmmm... does this happen all of the time, or do you get a grace period
> of a few minutes immediately after rebooting the FreeBSD box? Are you
> perhaps ending up with an awful lot of connections sitting in
> CLOSE_WAIT stage on the FBSD box?
>
> > The rcp behaves the same way - but with an added oddity... I can't seem
> > to 'rcp -r' directories. For example, say I have /tmp/test and in there
> > I have three files (a, b, and c.). When I try to rcp -r that directory,
> > I get the following:
> >
> > # rcp -r /tmp/test host:/tmp
> > rcp: /tmp/test/a/b: Not a directory
> > rcp: /tmp/test/a/b/c: Not a directory
> >
> > Very weird!
>
> Does saying:
>
> # rcp -r /tmp/test host:/tmp/
>
> (note the trailing '/') make a difference? This is by analogy to
> cp(1) where trailing slashes do have a similar sort of effect -- I
> think that's a feature of BSD-ish Unices but not SysV-ish flavours.
>
> > Anyone have any ideas? If I can't get this resolved I am going to have
> > to go back to the old SUN to SUN setup and scrap the FreeBSD machine.
>
> rcp(1) and rsh(1) are really considered as legacy stuff on FreeBSD
> nowadays. Most people will strongly advise you to use ssh(1) and
> scp(1) instead -- those are standard on Solaris 9 but you'll have to
> compile yourself up a copy on Solaris 2.6. You can use key based
> authentication with ssh-agent(1) in order to avoid having to put in
> passwords all the time: see the SSH FAQ at
>
> http://www.snailbook.com/faq/no-passphrase.auto.html
>
> Note too that sshd(8) under FreeBSD disallows root access by default,
> but there's a pretty obvious control in the /etc/ssh/sshd.conf config
> file.
>
> Cheers,
>
> Matthew
>
> --
> Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks
> Savill Way
> PGP: http://www.infracaninophile.co.uk/pgpkey Marlow
> Tel: +44 1628 476614 Bucks., SL7 1TH UK
>
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