Re: Get to the bottom of what is running my networks
Andrei POPESCU <andreimpopescu@gmail.com> writes:
[...]
> Unless ifupdown is smart enough (don't know, you have to research this)
> the "second" DHCP might override the default gateway of the "first"[1].
> Assuming you may want to connect other devices to the OpenWrt you
> probably don't want to tinker with it's DHCP server and should handle
> this on the client side. Useful reading:
Andrei suggests:
> man interfaces
> man dhcpclient.conf
Thanks.
What you feared above, did seem to be happening. But aren't you
supposed to be able to set gateway in /etc/network/interfaces?
`man interfaces' seems to indicate that I could by adding a line like
gateway xxx.xxx.xxx.xxx
to an interface.
But:
Stealing an idea from Tom H and Bob P, I find even without setting a
gateway, if I add `auto' to the stanzas it seems to come up like I want
it to, and both interfaces can be start/stopped with
/etc/init.d/networking start/stop
/etc/network/interfaces now looks like this:
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
allow-hotplug eth0
auto eth0
iface eth0 inet dhcp
# a secondary network interface
allow-hotplug eth1
auto eth1
iface eth1 inet dhcp
And route -n shows what I wanted to see:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
And it all survives rebooting.
Surprisingly, even when it was coming up with gateway in
192.168.2.0/24 network, it still seemed to work just fine. Probably
due to having the pet router hooked up with its wan port facing the
subnet 192.168.1.0 lan, and lan port facing subnet 192.168.2.0
[...]
> BTW, in a similar situation as yours I decided to connect the OpenWrt
> device (Asus WL 500gP v2) directly to the gateway via one of the
> "lan"[2] ports and with a static IP in the same subnet. This way I can
> use it as just another device on my lan and plan to use it as DNS and
> web server.
Interesting... I thought about trying that hookup at first, before
going the lan wan route on the test router. I thought it would be
more like a real setup if I had it as transfer point between
192.168.1.0 and 192.168.2.0.
I expect to throw different stuff at it and watch reactions until I
learn enough about openwrt and iptables to trust my self to run my own
router at the main gateway with wan facing cable modem.
> [2] most devices of this type actually implement the "wan" and "lan" via
> vlans and it's very under OpenWrt to disable this functionality and use
> the wan port as just another switch port.
Thanks, and vlans is how this one defaults.
Veering a little off topic here but:
I'm curious when you say you are going to be using embedded openwrt on
a router to run a dns server; Do you mean an honest to god real DNS
server running bind/named (or similar). I did notice that bind
software is available for recent builds of openwrt.
I don't know about it to hazard a guess myself but I guess you don't
think the small amount of available ram will be a factor in a dns
server or web server of your lans' proportions eh?
That would be a very nice kind of server to have... the size of a
smallish book, quiet, no fans running, not much heat... nice.
I wonder if you'd know if mine could do the same by these two ouputs:
(TP-Link WR1043ND running very recent openwrt Using:
openwrt-ar71xx-generic-tl-wr1043nd-v1-squashfs-factory.bin)
------- --------- ---=--- --------- --------
/proc/cpuinfo and `free'
cpuinfo
system type : Atheros AR9132 rev 2
machine : TP-LINK TL-WR1043ND
processor : 0
cpu model : MIPS 24Kc V7.4
BogoMIPS : 265.42
wait instruction : yes
microsecond timers : yes
tlb_entries : 16
extra interrupt vector : yes
hardware watchpoint : yes, count: 4, address/irw mask: [0x0000, 0x0e50, 0x0088, 0x0360]
ASEs implemented : mips16
shadow register sets : 1
kscratch registers : 0
core : 0
VCED exceptions : not available
VCEI exceptions : not available
------- --------- ---=--- --------- --------
free
total used free shared buffers
Mem: 29416 18872 10544 0 1440
-/+ buffers: 17432 11984
Swap: 0 0 0
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