RE: Basic linux network questions (long)
I figured out at least one problem: There's a typo in the Linux networking
HOWTO. In resolve.conf (I erroneously said route.conf, below), 'nameserver'
doesn't have a space! I somehow stumbled across the correct token in a man
page somewhere, fixed my resolve.conf, and now I've got name resolution.
That doesn't really explain why I never needed to do that before, unless the
intermediate fumbling around with ppp somehow whacked it.
Will look into the others very soon.
Thanks!
(and yes, I sent mail to the HOWTO maintainer about the typo)
Richard Wurdack
-----Original Message-----
From: Heather [mailto:star@betelgeuse.starshine.org]
Sent: Friday, March 08, 2002 3:00 PM
To: Richard Wurdack
Cc: debian-user@lists.debian.org; 'debian-laptop@lists.debian.org'
Subject: Re: Basic linux network questions (long)
> Hello,
>
> Sorry for the cross-post, but this thread has generic and laptop related
> issues.
>
> I installed Potato (running the default 2.2.19 kernel) on an IBM 600e
> Thinkpad about a month ago. I seem to have clobbered something
>
> This problem list is in chronological order. I'm not (necessarily)
looking
> for answers to the specific problems, but rather what tools I can use to
> diagnose them.
>
> Problem #1
>
> The original install seemed to pick up the PCMCIA support just fine, and
it
> appears to recognize my network card without any problems. I had to run
> dhcpcd manually, though to get an IP address. After that, everything
worked
> fine, except that I had to restart dhcpcd every time I rebooted.
perhaps having to do with entries in /etc/pcmcia/network.opts not telling it
to do dhcp?
> Problem #2
>
> Downloaded the 2.2.20 kernel sources from kernel.org (no, I didn't use the
> Debian package - I kind of wanted to step through the process manually)
> Realized that the laptop is distracting me at work, so I decide to take it
> home. Built the 2.2.20 kernel. Boots fine.
>
> Of course, I don't have a broadband connection at home (dialup only). I
> "sneaker-net" the TP600e winmodem driver from my wife's Win2K box, rebuild
> the kernel (because I forgot to include floppy support!), build and
install
> the driver, and get ppp up and running. Now I can dial in from my linux
> box. Cool.
>
> I discover, however, that if I shut the lid on the box (it might be
> hibernating, don't know - I didn't doing anything special for APM), and
> reopen it, pon can't dial out without a reboot (just like Windows!).
you do need to build in apm support to the kernel, if it's going to be asked
to deal with APM interrupts.
Nowadays some boxen are much better at speaking ACPI, but the degrade after
a kernel build suggests that APM was probably enough. In "make menuconfig"
this is at the bottom of one of the upper sections.
You'd surely want to visit at least "general" "usb" and "sound" anyway.
> Problem #3
> This is the real blocking issue. Today I bring the laptop back to work,
> because I want to download some big packages. First, no pcmcia, because I
> didn't really do everything I needed to when I build 2.2.20 (specifically,
> no pcmcia module in /lib/modules/linux2.2.20). Ok, no big deal, since I
> still have my 2.2.19 kernel in /boot. Boot 2.2.19, run dhcpcd (as usual,
> see Problem #1). Domain names aren't resolving (ping www.yahoo.com
> <http://www.yahoo.com> - host unreachable), but I can ping IP addresses.
David Hinds' stuff available as source seperately or from unstable.
I really do recommend kernel-package, it reduces a lot of these headaches
down to "did I remember to build all my debs?" :)
Problem 3.b (can only ping by IP) suggests that you should try ping the IP
of your router. Run route -n and see if you even *have* a default route.
If you don't, set it to a machine on your local subnet that is willing to
forward packets. If you're on private addresses (192.168.*.*,
172.16-31.*.*,
10.*.*.*) it will also need to masq/nat your addresses for real world use.
> Looked at the networking HOWTO - the only thing I found that looked wrong
> was that route.conf was empty, so I added our DNS servers. I can ping the
> DNS servers (by IP address), but name resolution still fails.
In theory DHCP can give you the resolv values; in practice most dhcpd admins
are lazy and never heard of the idea. Sigh.
> All the earlier problems are things I can work around and tolerate. The
> last one is pretty much keeping me off the network.
All you need is one stable DNS server that is either on the local-net (thus
you can reach it "directly") or that the default route is correctly passing
you to.
I deeply suspect incorrect sub-masking - since that's what gives me these
symptoms, when I'm going to fast setting up someone on a /27 network - but
since you pick up your address by DHCP I really hope that's not it. If it
*is* ...
1. go offer to buy your dhcpd admin a burger if he will pretty
please fix it. He doesn't get the ice cream til it works :)
2. you can work around by having dhcpcd pick up the lease, noting
down the values, then using ifconfig *explicitly* with the
correct netmask and broadcast. When your lease fails you will
again be handed the crappy data and need to poke it in the ribs.
3. If the dhcpd admin is a receptionist, a dork, or never there,
you can use the rarely-needed values in /etc/pcmcia/network.opts
for post-setup and pre-teardown to force the fixes in. Probably
you would need to have awk or grep "read" ifconfig or /proc to
learn your assignment for this pass.
> Questions:
>
> 1. I checked that there was a symlink to dhcpcd from /etc/rc2.d
(S13dhcpcd),
> but I don't see any messages in /var/log/syslog. The only thing I see is
> the successful detection of the Ethernet adapter and it launching
./network
> start eth0 (which is something I'll be taking a look at shortly).
I think the client daemon is only going to be invoked on a card event...
but I can easily be wrong, because what works for me is pump.
> 2. Any hints as to why I didn't get a pcmcia module in my kernel build? I
> ran 'make modules modules-install', which I had assumed would handle that
> for me.
pcmcia sources are seperate; when you go through *their* ./configure (or
is it make config?) they ask you where the kernel sources are, and choose
applicable magic words based on that... *their* make install adds a bunch
of modules not in the normal kit.
Which would be incompatible (vaguely) with the 2.4.x builtin-pcmcia stuff,
but you chose 2.2.20 so ignore that for now :D
> 3. Is there some way I can watch (debug) the DNS lookup and get a clue as
to
> why it's failing?
You can use nslookup and tell it to go to explicit servers, and try to do
lookups "by hand". A bit better for debugging than telnetting port 80 to
debug web servers, I'd say.
> Thanks in advance,
> Richard Wurdack
Good luck and let us know how this helps, or doesn't...
* Heather Stern * star@ many places...
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