packet forwarding

[Yance Kowara]

Hi all,

What's the difference between

gateway_enable="YES" in /etc/rc.conf

and

net.inet.ip.forwarding=1 in /etc/sysctl.conf

Regards,

Yance



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[Igor Robul]

Post by Yance Kowara
Hi all,
What's the difference between
gateway_enable="YES" in /etc/rc.conf
and
net.inet.ip.forwarding=1 in /etc/sysctl.conf
Regards,

There are no differences, you can check this by greping gateway_enable
in /etc/rc.d/*.

[Dan Nelson]

Post by Yance Kowara
What's the difference between
gateway_enable="YES" in /etc/rc.conf
and
net.inet.ip.forwarding=1 in /etc/sysctl.conf

case ${gateway_enable} in
[Yy][Ee][Ss])
echo -n ' IP gateway=YES'
sysctl net.inet.ip.forwarding=1 >/dev/null
;;
esac

So the answer is: nothing, except that adding the line to sysctl.conf
enables packet forwarding before interfaces are configured and other
network variables are set, so you may get spurious "host unreachable"
errors from systems trying to route through the box when it boots up.

[Yance Kowara]

Thank you for the clarification about setting GATEWAY
(packet forwarding) in systl.conf and rc.conf.

The handbook suggested that "Over five hundred system
variables can be read and set using sysctl(8)" ...

Any clue as to where I can see those "over five
hundred system variables"? ... just being curious ...

Also, is this sysctl.conf a unique feature of FreeBSD
or a feature of nay *NIX O/S?

Kind regards,

Yance




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[Volker Kindermann]

Hi Yance,

Post by Yance Kowara
Any clue as to where I can see those "over five
hundred system variables"? ... just being curious ...

some are in the manpage of sysctl. There is also this hint:

"More variables than these exist, and the best and likely only place to
search for their deeper meaning is undoubtedly the source where they
are defined.

Post by Yance Kowara
Also, is this sysctl.conf a unique feature of FreeBSD
or a feature of nay *NIX O/S?

At least OpenBSD and Linux have this feature, too.


-volker

[Giorgos Keramidas]

Post by Yance Kowara
The handbook suggested that "Over five hundred system
variables can be read and set using sysctl(8)" ...
Any clue as to where I can see those "over five
hundred system variables"? ... just being curious ...

To see a list of all the sysctl variables:

sysctl -a | more

Not all of these are read-write though, so it may not be possible to set
all of them.

[Bob Middaugh]

Yance Kowara writes:

Thank you for the clarification about setting GATEWAY (packet
forwarding) in systl.conf and rc.conf.

The handbook suggested that "Over five hundred system variables can be
read and set using sysctl(8)" ...

Any clue as to where I can see those "over five hundred system
variables"? ... just being curious ...

Also, is this sysctl.conf a unique feature of FreeBSD or a feature of
nay *NIX O/S?

Kind regards,

Yance


sysctl -a

Check out: http://sysctl.enderunix.org/index.php?tip_id=1&lang=en

There are 80+ documented there. The sites goal is to get as many as
possible documented, so if you come across some that aren't there, and
you know what they do, please submit.

Someone was looking for window scaling, rfc 1323 covers that I think:
net.inet.tcp.rfc1323 enables high performance TCP extensions

Bob