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Strange route problem

Linux Kernel, Network, and Services configuration.
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Sophjer
Posts: 7
Joined: 2016-03-27 21:56

Strange route problem

#1 Post by Sophjer »

I have a VM with two nics, eth0 and eth1. eth0 is connected to our DMZ and has an IP 10.10.10.17.
The second nic, eth1 is connected to a vlan on our inside interface and has an IP 192.168.105.20.

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/etc/network/interfaces

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source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0

iface eth0 inet static

        address 10.10.10.17
        netmask 255.255.255.0
        network 10.10.10.0
        broadcast 10.10.10.255
        gateway 10.10.10.1

# The secondary network interface
allow-hotplug eth1

iface eth1 inet static

        address 192.168.105.20
        netmask 255.255.255.0
        network 192.168.105.0
        broadcast 192.168.105.255
        gateway 192.168.105.1

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route -n

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Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.10.10.1      0.0.0.0         UG    0      0        0 eth0
10.10.10.0      0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.105.0   0.0.0.0         255.255.255.0   U     0      0        0 eth1
What's strange is that I can ping other servers on .105, but I cannot ping machines on our .5. Yet, any machine on vlan105 can ping to vlan5. Any ideas? I need this server in our DMZ to talk to db servers in our vlan5.
Thanks in advance

Sophjer
Posts: 7
Joined: 2016-03-27 21:56

Re: Strange route problem

#2 Post by Sophjer »

Ok I've more or less resolved this. I found changing the netmask to

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255.255.0.0
fixes things, which makes sense I can now reach other subnets. What I don't understand is that other machines in the same subnet can ping others while having

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255.255.255.0
as their mask. :?: :?:

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