Problem with ping/telnet
murali nagarajan
muralin at gdatech.com
Thu Feb 7 06:59:45 EST 2002
Hello,
I have received many responses and here I am responding with what I have
tried so far and some more info to solve this issue.
Consolidated answeres to many questions raised in the responses:
- The File system has the glibc resolver libraries, all of those mentioned
in the "man pages of nsswitch.conf". All those /lib/libnss_files and the
symbolic links are verified correctly.
- The nsswitch.conf has entries for all important service switches including
protocols and services.
- For the name resolution in the "hosts" entry of nsswitch.conf, "files" is
given the precedence. The settings in the /etc/hosts are ok.
- PLEASE note that the NFS file system in use has been successfully used
with an evaluation board where I could run all network related programs
incl. ping & telnet. I have made no changes to the file system.
****One significant difference between the eval. board and the curent one is
that I DO NOT run /sbin/init when the kernel boots and therby preventing the
boot scripts execution. I run the /bin/sh directly. (Inittab was set to 3
and then 1 without any differnce)
Another observation:
--------------------
I have run set of boot scripts from the bash, but it looks like either they
are insufficient or not done correctly. This is because when I try to
perform a insmod of a very simple skeleton driver, I get "unresolved
symbols - even for printk". But I do have a ksyms file under /proc. Probably
the acess to these files is somehow not taking place. (The kernel has
loadable Module support enabled!)
My questions:
- Is there any simple script file that I can run when I do not boot the
system via /sbin/init.
- What are all the necessary steps that needs to be performed if we have to
replace the /sbin/init boot process.
- PING not being able to read /etc/processes and TELNET not being able to
read the /etc/services and INSMOD failing due to unresolved symbols :
Anything in common?
Thanks to all who have responded.
With best regards,
Murali
----- Original Message -----
From: "Jeffrey D. Kowing" <jeffrey.d.kowing1 at jsc.nasa.gov>
To: "David A. Gatwood" <dgatwood at gatwood.net>
Cc: "murali nagarajan" <muralin at gdatech.com>;
<linuxppc-dev at lists.linuxppc.org>
Sent: Tuesday, February 05, 2002 5:03 PM
Subject: Re: Problem with ping/telnet
> David A. Gatwood writes:
> >
> > On Tue, 5 Feb 2002, murali nagarajan wrote:
> >
> > > With your info, I am able to do a telnet from my board to the host,
only if
> > > I specify the port number. What surprises me is that the presence of
both
> > > /etc/services (entry to telnet is available with a port number) and
the
> > > /etc/protocols files. For some reason, may be the boot process is
unable to
> > > read these information. But when I want to do a telnet to my board
from my
> > > host iMAc, I am unable to do. I get an error message "connection
refused".
> >
> > This sounds vaguely familiar like I've run into it before, but I can't
> > remember where.
> >
> > The boot process doesn't read /etc/services. That's read on-the-fly by
> > the telnet program itself with calls to either getservbyname or
> > getservent, which are standard C library calls, and should always work
if
> > the service is listed and the files (and directory) are readable by the
> > user that telnet is being run as.
>
> It sounds like you might be missing some of the glibc resolver
> libraries that allow programs to access the various databases (i.e.,
> things like /etc/services and /etc/protocols.) In particular, I think
> you might be missing the /lib/libnss_files.so. There is a discussion
> of this somewhere in the glibc info pages as I recall. Also, your
> /etc/nsswitch.conf file is important for determining which source of
> information takes precedence (for instance, in the case of name
> resolution, do you use /ect/hosts first or a domain name server
> first).
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