#[Interfaces]
#-----------------

auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address 192.168.2.1
netmask 255.255.255.0
network 192.168.2.0
broadcast 192.168.2.255
gateway 192.168.2.1
#
#iface lo inet loopback
auto eth1
iface eth1 inet static
address 10.8.1.20
netmask 255.0.0.0
network 10.8.1.0
broadcast 10.8.1.255
gateway 10.8.1.1


## dhcpd.conf###############
#----------------------------
default-lease-time 600;
max-lease-time 7200;
option subnet-mask 255.255.255.0;
option broadcast-address 192.168.2.255;
option routers 192.168.2.1;
option domain-name-servers  208.67.222.222, 208.67.220.220
option domain-name "mydomain.example";

subnet 192.168.2.0 netmask 255.255.255.0 {
range 192.168.2.150 192.168.2.200;
}


## IP TABLES ---------------------

iptables --flush 
iptables --table nat --flush
iptables --delete-chain
iptables --table nat --delete-chain
iptables --table nat --append POSTROUTING --out-interface eth1 -j MASQUERADE
iptables --append FORWARD --in-interface eth0 -j ACCEPT
#echo 1 > /proc/sys/net/ipv4/ip_forward
iptables-save

# transparent squad proxy server configuration
iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp --dport 80 -j DNAT --to-destination 192.168.2.1:3128
iptables -t nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128
iptables-save


### tcpdump command ######
sudo tcpdump -i eth0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
12:41:45.125984 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 00:1b:38:f0:03:84 (oui Unknown), length 300
12:41:45.468362 IP6 fe80::240:f4ff:feb1:ccda.mdns > ff02::fb.mdns: 0 PTR (QM)? 255.255.255.255.in-addr.arpa. (46)
12:41:45.468418 IP noc-server.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 255.255.255.255.in-addr.arpa. (46)
12:41:46.469691 IP6 fe80::240:f4ff:feb1:ccda.mdns > ff02::fb.mdns: 0 PTR (QM)? 255.255.255.255.in-addr.arpa. (46)
12:41:46.469735 IP noc-server.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 255.255.255.255.in-addr.arpa. (46)
12:41:48.472128 IP6 fe80::240:f4ff:feb1:ccda.mdns > ff02::fb.mdns: 0 PTR (QM)? 255.255.255.255.in-addr.arpa. (46)
12:41:48.472174 IP noc-server.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 255.255.255.255.in-addr.arpa. (46)
12:41:50.675919 IP6 fe80::240:f4ff:feb1:ccda.mdns > ff02::fb.mdns: 0 PTR (QM)? 0.0.0.0.in-addr.arpa. (38)
12:41:50.675958 IP noc-server.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 0.0.0.0.in-addr.arpa. (38)
12:41:51.677198 IP6 fe80::240:f4ff:feb1:ccda.mdns > ff02::fb.mdns: 0 PTR (QM)? 0.0.0.0.in-addr.arpa. (38)
12:41:51.677243 IP noc-server.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 0.0.0.0.in-addr.arpa. (38)
12:41:51.906964 IP 192.168.10.194 > igmp.mcast.net: igmp v3 report, 1 group record(s)

## LOG messages#########
  tail -f /var/log/dmesg
[   13.398407] HDA Intel 0000:00:1b.0: setting latency timer to 64
[   13.728601] EXT4-fs (sda6): mounted filesystem with ordered data mode. Opts: (null)
[   14.023805] type=1400 audit(1308639288.407:5): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=777 comm="apparmor_parser"
[   14.025555] type=1400 audit(1308639288.407:6): apparmor="STATUS" operation="profile_load" name="/usr/share/gdm/guest-session/Xsession" pid=776 comm="apparmor_parser"
[   14.027647] type=1400 audit(1308639288.407:7): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=777 comm="apparmor_parser"
[   14.028167] type=1400 audit(1308639288.407:8): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=777 comm="apparmor_parser"
[   14.045982] type=1400 audit(1308639288.427:9): apparmor="STATUS" operation="profile_load" name="/usr/bin/evince" pid=778 comm="apparmor_parser"
[   14.060571] type=1400 audit(1308639288.447:10): apparmor="STATUS" operation="profile_load" name="/usr/lib/cups/backend/cups-pdf" pid=782 comm="apparmor_parser"
[   14.061544] type=1400 audit(1308639288.447:11): apparmor="STATUS" operation="profile_load" name="/usr/sbin/cupsd" pid=782 comm="apparmor_parser"
[   14.410477] e1000e 0000:00:19.0: irq 40 for MSI/MSI-X