When do I deen to restart the network initialization? To reboot?

Is there any documentation available about the run-time state of the
TCP/IP networking subsystem? Especially, which changes to the settings
work immediately after "ifconfig" or "route". Or any other particular way
to change the TCP/IP settings. What is the logic here?

Then, how are the changes made permanent? Which files all in all are
affected? In /etc, /etc/sysconfig, /etc/rc.d? Elsewhere?

When do you need to run '/etc/init.d/network restart'? Or is
'...reload' sometimes enough (they are the same in my RH9)? How about
ifdown/ifup only? (BTW, why don't I have man pages for ifup/ifdown?)
Are there other commands to re-initialize?

If that is not enough, when do I have to reboot and why?

Can the Ethernet card save its state between reboots? Is it possible that
you need to power-cycle to get new settings in effect? Seems that I have
experienced this.

Is there a document that takes into account the
differences in distros? Why are there differences in the first place? Is
there any effort to harmonize such a trivial detail?

In article <(E-Mail Removed)>,
Anssi Porttikivi wrote:
A lot of questions. I'll answer those I can.

> Then, how are the changes made permanent? Which files all in all are
> affected? In /etc, /etc/sysconfig, /etc/rc.d? Elsewhere?

That's a distro-specific question, and the answer is in the shell
scripts which read those files. In RH I believe those are in the
/etc/init.d directory.

> ifdown/ifup only? (BTW, why don't I have man pages for ifup/ifdown?)

Because whoever wrote those scripts did not see fit to write a man page.

> If that is not enough, when do I have to reboot and why?

Changes in hardware or in your kernel. Or when a power outage may exceed
the capability of your UPS.

> Can the Ethernet card save its state between reboots? Is it possible that

Uh, high-level TCP/IP settings (which you are talking about) are not
saved by the card itself. Some cards do have onboard NVRAM chips which
save low-level settings, such as media type, autonegotiation, or duplex.
I'll bet the MAC address itself is in NVRAM.

> you need to power-cycle to get new settings in effect? Seems that I have
> experienced this.

You might have misunderstood the cause or effect. You did a cold reboot
and that worked, but it probably was not the only way to do it.

> Is there a document that takes into account the differences in distros?

I don't know. Anyway, you might be better off by choosing one distro and
learning how/why it works.

> Why are there differences in the first place? Is

Because different people are producing them, and they have different
ideas about how things should be done.

> there any effort to harmonize such a trivial detail?

1. Yes
2. Who says it's trivial?
3. Why should everything be the same? Diversity and choice is good.

The underlying software is more or less the same, and if you understand
how it is done in one distro, you can figure out how it's done in any
other one. BTW "service network restart" is not understanding: it's a
high level tool which hides the low-level details.
--
/dev/rob0 - preferred_email=i$((28*28+28))@softhome.net
or put "not-spam" or "/dev/rob0" in Subject header to reply

On Mon, 22 Sep 2003 11:31:59 +0300, Anssi Porttikivi <(E-Mail Removed)> wrote:
> Is there any documentation available about the run-time state of the
> TCP/IP networking subsystem? Especially, which changes to the settings
> work immediately after "ifconfig" or "route". Or any other particular way
> to change the TCP/IP settings. What is the logic here?

You can manually change settings with ifconfig or route and they take
effect immediately. In fact, you can make ifconfig changes on the fly
without bringing an interface down. Note that IP changes may require
routing changes. If an interface is brought down, any routes using that
interface disappear. Such ifconfig or route changes are temporary (until
shutdown or networking is restarted)

> Then, how are the changes made permanent? Which files all in all are
> affected? In /etc, /etc/sysconfig, /etc/rc.d? Elsewhere?

Generally somewhere under /etc/sysconfig, but it depends upon the distro.
Some settings for hotplug devices (like pc cards) might be made under
/etc/pcmcia.

> When do you need to run '/etc/init.d/network restart'? Or is
> '...reload' sometimes enough (they are the same in my RH9)? How about
> ifdown/ifup only? (BTW, why don't I have man pages for ifup/ifdown?)
> Are there other commands to re-initialize?

You only need to restart the network if updates affected network
components or you want to get back to your normal config after mucking
about.

> If that is not enough, when do I have to reboot and why?

Reboot should rarely be necessary. You can generally refresh most things
by changing runlevel (man telinit), although, you likely need to do that
from the console, not X. For example, runlevel 2 is without networking,
so if you telinit 2, and then telinit 3 (or 5), any networking daemons
that may have been updated should end up reloaded.

> Can the Ethernet card save its state between reboots? Is it possible that
> you need to power-cycle to get new settings in effect? Seems that I have
> experienced this.

You may only need to power cycle (shut down completely) when switching
between Windows and Linux, because Windows sometimes leaves things in an
unusual state.

> Is there a document that takes into account the
> differences in distros? Why are there differences in the first place? Is
> there any effort to harmonize such a trivial detail?

With United Linux, they are becoming more similiar. For example SuSE has
switched from rc.config file and rc.config.d directory to /etc/sysconfig
for most system config files and similar script names, but not all paths
are exactly the same.

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