default route: strange behaviour

fr_laz · 07-07-2005, 07:04 AM

Hi all!

I know this question will look stupid... but, anyhow, I just don't know why this doesn't work.
I wanted to give a try to netbsd, I had allready try to install it, but my dd isn't recognized by the installer: it can see it, but not write on it... that's a bit of a problem.

I also wanted to try qemu, an emulator, so I installed qemu on my debian and installed a netbsd and winXP image.

my windows image works quite well, I can access both my lan and the internet. So that's not a qemu issue, nor a config problem from my Linux box.

on my netbsd, I did the following:

Code:

# ifconfig ne2 172.20.0.2/16
# ping 172.20.0.1
PING 172.20.0.1 (172.20.0.1) 56 bytes of data.
64 bytes from 172.20.0.1: icmp_seq=1 ttl=255 time=0.941 ms
64 bytes from 172.20.0.1: icmp_seq=2 ttl=255 time=0.265 ms
# route add default 172.20.0.1
add net default: gateway 172.20.0.1
# ping 172.20.0.1
no answer!
# route delete default 172.20.0.1
delete net default: gateway 172.20.0.1
# ping 172.20.0.1
64 bytes from 172.20.0.1: icmp_seq=1 ttl=255 time=0.941 ms
64 bytes from 172.20.0.1: icmp_seq=2 ttl=255 time=0.265 ms

so, as soon as I configure a default gateway, I loose the connexion with the debian box!
of course, I cannot ping the lan or internet either.

What's more, after adding the default route I cannot even ping my netBSD's own IP!

I als tried to add:

Code:

defaultrouter="172.20.0.1"

in /etc/rc.conf and then restart the network, but the default route isn't taken into account!

so any idea is welcome!

scuzzo84 · 07-07-2005, 10:21 AM

# route add default 172.20.0.1

or in rc.conf

defaultroute="172.20.0.1"

not

defaultrouter="172.20.0.1"

read guide

fr_laz · 07-07-2005, 11:24 AM

thanks... this explains why the route wasn't taken into account in rc.conf... but it gives the same result as in command line: as soon as the route is set up, my interface doesn't answer anymore, I cannot pîng the gateway, nor the NIC's IP itself!
what's more, it doesn't say that the ping were lost... there is no answer at all from the ping command!
I tried a nslookup which doesn't work either (which isn't a surprise).

As for the remark about reading doc... that's what I've done before posting. I know that it's _very_ boring to answer total newby question, and I am one in *bsd - sorry about that.

[edit] Queer: I have no network access from the netBSD virtual box, but I can ping it from the real debian box and from the virtual winXP!

scuzzo84 · 07-07-2005, 02:53 PM

is this a box or an emulated thing like qemu?

maybe try tcpdump

fr_laz · 07-08-2005, 06:47 AM

Hi,

it's an emulated netBSD thanks to qemu (real OS beeing a debian sarge).

here's my routing table (netstat -rn):

Code:

Internet:
Destination        Gateway            Flags     Refs     Use    Mtu  Interface
0/8                link#1             UC          0        0      -  ne2 =>
default            172.22.0.1         UGS         0        4      -  ne3
127/8              127.0.0.1          UGRS        0        0  33196  lo0
127.0.0.1          127.0.0.1          UH          1        0  33196  lo0
172.22/16          link#2             UC          1        0      -  ne3
172.22.0.1         00:ff:19:f6:38:35  UHLc        1        2      -  ne3

my nics are configured this way:
ifconfig ne2 0.0.0.0 (I'll use it later... as a matter of fact, ne2 beeing up or down doesn't change a thing to my problem)
ifconfig ne3 172.22.0.2/16

I made some tests with tcpdump...
My ping make no output (ping -c 3 172.22.0.1 doesn't stop by itself, I must ^C it).
I don't see the pings in tcpdump.
I used tcpdump on the Linux box, it sees nothing as well.

But, I can ssh into my Linux machine, from the netBSD!
And I see these ssh packets in both (Linux & BSD) tcpdump outputs.

when I delete the default route, everything works fine (ping and tcpdump produce their usual output)

so... I'll go on like this, but I really don't understand what happens!

scuzzo84 · 07-08-2005, 09:27 AM

I thought you cant change the ips and whatever with qemu and you use ip-nat whatever.....sort of like TAP with linux. I will leave it at this, for me since I recall you cant do this with qemu, I may be wrong.

fr_laz · 07-08-2005, 09:57 AM

Hi,

well, usually, you'll use the user-net option of qemu to configure nat in the real box. So as all is configured, you don't have to change network settings.
but I wanted to test inter-vlan routing, clustering and other things which need more machines and network equipement than I have...

so I use tun interfaces that I connect together through brctl (Linux bridging tool). That works very well: every virtual machine I've set up appear as if they were on the same switch, and I'll be able to configure vlans on the real linux box, I'll use the netBSD to set up a virtual gateway between the vlans I'll configure and the real network... at the moment I'm looking at pf which looks to be more powerfull than iptables...

thanks for your replies!