I am not really sure how this is possible but I have a linux(ubuntu 14.04) box with 2 interfaces. eth0 is connected to our lan 192.168.0.* and eth1 is connected to a dlink wifi router on network 192.168.3.* .
Wifi network is only available for mobile devices. They are only supposed to access a web application installed on the box. I want to prevent any eventualities such as accessing 192.168.0.* network even if someone gets authorized access to the box via ssh.
Is something like that possible? if yes please explain how to and give any resource you have for better understanding. Networking is not my strongest area but can understand much of the concept when explained clearly so please bear with me.
EDIT
In /etc/sysctl.conf I have now net.ipv4.ip_forward=0 with sudo -p /etc/sysctl.conf with a restart of the machine. But it didn't work. I can ping 192.168.0.* network
#sysctl -a
net.ipv4.conf.all.accept_local = 0
net.ipv4.conf.all.accept_redirects = 1
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.all.arp_accept = 0
net.ipv4.conf.all.arp_announce = 0
net.ipv4.conf.all.arp_filter = 0
net.ipv4.conf.all.arp_ignore = 0
net.ipv4.conf.all.arp_notify = 0
net.ipv4.conf.all.bootp_relay = 0
net.ipv4.conf.all.disable_policy = 0
net.ipv4.conf.all.disable_xfrm = 0
net.ipv4.conf.all.force_igmp_version = 0
net.ipv4.conf.all.forwarding = 0
net.ipv4.conf.all.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.all.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.all.log_martians = 0
net.ipv4.conf.all.mc_forwarding = 0
net.ipv4.conf.all.medium_id = 0
net.ipv4.conf.all.promote_secondaries = 0
net.ipv4.conf.all.proxy_arp = 0
net.ipv4.conf.all.proxy_arp_pvlan = 0
net.ipv4.conf.all.route_localnet = 0
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.all.secure_redirects = 1
net.ipv4.conf.all.send_redirects = 1
net.ipv4.conf.all.shared_media = 1
net.ipv4.conf.all.src_valid_mark = 0
net.ipv4.conf.all.tag = 0
EDIT 2
below is my iptables
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Thanks in advance.
