Multiple network interfaces, routing configuration. IP rule fails (debian based instances)

amazon ec2debian-wheezynetworkingrouting

I have debian wheezy based instance with 2 network interfaces (Primary, Secondary).
My setup flow:

vim /etc/network/interfaces

auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet dhcp

ifup eth1
ifconfig -a

eth0      Link encap:Ethernet  HWaddr 0a:1e:17:4a:dc:0a  
          inet addr:172.31.7.189  Bcast:172.31.15.255  Mask:255.255.240.0
          inet6 addr: fe80::81e:17ff:fe4a:dc0a/64 Scope:Link
eth1      Link encap:Ethernet  HWaddr 0a:74:e6:54:ba:c9  
          inet addr:172.31.10.172  Bcast:172.31.15.255  Mask:255.255.240.0
          inet6 addr: fe80::874:e6ff:fe54:bac9/64 Scope:Link
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host

Okay, all fine in this point and both private ips (172.31.7.189, 172.31.10.172) is accessible to ping.

echo "200 out" >> /etc/iproute2/rt_tables

# reserved values
#
255 local
254 main
253 default
0   unspec
#
# local
#
#1  inr.ruhep
200 out

route -n

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.31.0.1      0.0.0.0         UG    0      0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0 eth0
172.31.0.0      0.0.0.0         255.255.240.0   U     0      0        0 eth0
172.31.0.0      0.0.0.0         255.255.240.0   U     0      0        0 eth1

ip route add default via 172.31.0.1 dev eth1 table out

ip rule add from 172.31.0.0/20 table out

Write failed: Broken pipe

Now instance is not accessible through ssh.
Please help, what i doing wrong?

My workflow is based an tutorial
https://www.lisenet.com/2014/create-and-attach-a-second-elastic-network-interface-with-eip-to-ec2-vpc-instance/comment-page-1/#comment-105

Best Answer

Problem solved.

I tried to define ip rule for whole network 172.31.0.0/20, that's wrong.

When i use private ip from secondary network interface all works fine.

ip route add default via 172.31.10.172 dev eth1 table out
ip rule add from 172.31.10.172 table out

where 172.31.10.172 is private ip from network interface eth1

Instead of "ip rule add from 172.31.0.0/20 table out ..."

P.S. Big thanks to Tomas Nevar

Related Topic