Network - Redhat Linux

from system(10.10.10.37)  i did use this command
 
route add -net 10.10.20.0 netmask 255.255.255.0 gw 10.10.10.6 dev eth0

still not working. what is wrong here.

[root@smtp ~]# ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:0C:29:09:87:50
          inet addr:10.10.10.37  Bcast:10.10.10.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe09:8750/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:151297 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5008 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:649322 (634.1 KiB)  TX bytes:360510 (352.0 KiB)

[root@smtp ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.10.20.0      10.10.10.6      255.255.255.0   UG    0      0        0 eth0
10.10.10.0      0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0
169.254.0.0     0.0.0.0         255.255.0.0     U     1002   0        0 eth0

[root@smtp ~]# ping 10.10.20.4
PING 10.10.20.4 (10.10.20.4) 56(84) bytes of data.
64 bytes from 10.10.20.4: icmp_seq=1 ttl=64 time=0.335 ms
64 bytes from 10.10.20.4: icmp_seq=2 ttl=64 time=0.259 ms

But I am unable to ping 10.10.20.2.  

From 10.10.20.4 system i can ping 10.10.20.2.

[root@smtp ~]# ping 10.10.20.2
PING 10.10.20.2 (10.10.20.2) 56(84) bytes of data.

Hello,

Simpliest (but not dirty) way for your problem - set netmask to /16 255.255.0.0 and all systems can be in one subnet.

I have many devices manually configured which i don't want to change. Is there any other better way. Why static route won' t work?

Network one - 10.10.10.0/24
Network two - 10.10.20.0/24

U can show this command output from both devices?
ip route show

[root@smtp ~]# ifconfig eth0 | grep inet
          inet addr:10.10.10.37  Bcast:10.10.10.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe09:8750/64 Scope:Link
[root@smtp ~]# ip route show
10.10.20.0/24 via 10.10.10.6 dev eth0
10.10.10.0/24 dev eth0  proto kernel  scope link  src 10.10.10.37
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1
169.254.0.0/16 dev eth0  scope link  metric 1002





[root@ns ~]# ifconfig eth0 | grep inet
          inet addr:10.10.20.4  Bcast:10.10.20.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:febb:a670/64 Scope:Link
[root@ns ~]# ifconfig eth2 | grep inet
          inet addr:10.10.10.6  Bcast:10.10.10.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:febb:a684/64 Scope:Link
[root@ns ~]# ip route show
10.10.20.0/24 dev eth0  proto kernel  scope link  src 10.10.20.4
192.168.0.0/24 dev eth1  proto kernel  scope link  src 192.168.0.18
10.10.10.0/24 dev eth2  proto kernel  scope link  src 10.10.10.6
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1
169.254.0.0/16 dev eth0  scope link  metric 1002
169.254.0.0/16 dev eth1  scope link  metric 1003
169.254.0.0/16 dev eth2  scope link  metric 1004
default via 192.168.0.254 dev eth1







[root@mail ~]# ifconfig eth0 | grep inet
          inet addr:10.10.20.2  Bcast:10.10.20.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:feaf:56f7/64 Scope:Link
[root@mail ~]# ip route show
10.10.20.0/24 dev eth0  proto kernel  scope link  src 10.10.20.2
10.10.10.0/24 via 10.10.20.4 dev eth0
192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1
169.254.0.0/16 dev eth0  scope link  metric 1002
default via 10.10.20.1 dev eth0


I want able to ping from 10.10.10.37 to 10.10.20.2 AND
from 10.20.10.2 to 10.10.10.37 vice versa.


I am using  ns system as router which have access to both network.

All routing configuration fine (mail:  10.10.10.0/24 via 10.10.20.4   smtp:  10.10.20.0/24 via 10.10.10.6).

May u need enable forwarding on ns node:
echo "net.ipv4.ip_forward = 1" >> /etc/sysctl.conf
sysctl -p

Can u see forwarded packet in iptables (iptables -nvL FORWARD)?

route add -net 10.10.20.0 netmask 255.255.255.0 gw 10.10.10.6 dev eth0

How do i make this permanent.

Hello,

U need create files: /etc/sysconfig/network-scripts/route-eth0 on both servers with following contents:
10.10.20.0/24 via 10.10.10.6 dev eth0
and
10.10.10.0/24 via 10.10.20.4 dev eth0