[SOLVED] ip forwarding doesn't work

drManhattan · 02-15-2011, 12:01 PM

Hi

I have 2 guest machines on 1 VBox host installed :
- one guest with hostname 'debian' is configured as follows and has IP Forwarding enabled to be able to route traffic from eht1 to eth0.

Code:

eth0      Link encap:Ethernet  HWaddr 08:00:27:f1:ef:5f  
          inet addr:10.0.2.1  Bcast:10.0.2.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fef1:ef5f/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:22 errors:0 dropped:0 overruns:0 frame:0
          TX packets:75 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:1504 (1.4 KiB)  TX bytes:8665 (8.4 KiB)

eth1      Link encap:Ethernet  HWaddr 08:00:27:fd:74:81  
          inet addr:192.168.56.199  Bcast:192.168.56.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fefd:7481/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:234 errors:0 dropped:0 overruns:0 frame:0
          TX packets:182 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:25428 (24.8 KiB)  TX bytes:28130 (27.4 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:8 errors:0 dropped:0 overruns:0 frame:0
          TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:480 (480.0 B)  TX bytes:480 (480.0 B)

IP Forwarding is configured as follows :

Code:

echo 1 > /proc/sys/net/ipv4/ip_forward
/etc/sysctl.conf:
net.ipv4.ip_forward = 1

- Second guest with hostname 'ldap1' has the following config :

Code:

eth0      Link encap:Ethernet  HWaddr 08:00:27:12:1c:9b  
          inet addr:192.168.56.200  Bcast:192.168.56.255  Mask:255.255.255.0
          inet6 addr: fe80::a00:27ff:fe12:1c9b/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:791 errors:0 dropped:0 overruns:0 frame:0
          TX packets:385 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:119480 (116.6 KiB)  TX bytes:43738 (42.7 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:120 errors:0 dropped:0 overruns:0 frame:0
          TX packets:120 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:17920 (17.5 KiB)  TX bytes:17920 (17.5 KiB)

When I try to ping from 'ldap1' whatever IP or FQDN on the internet, it doesn't work.

What is wrong ?

thx for help

samborambo · 02-15-2011, 01:37 PM

You also need a forwarding rule in iptables. There are lots of howtos on ip forwarding. Google it.

Sam.

drManhattan · 02-16-2011, 04:45 PM

thx 'samborambo' i used this link.
Your suggestion was what I was looking for.

thx again.