IP Forwading on Ubuntu

Beberapa waktu lalu Server Ubuntu 8.04 dah bisa portforwading, dan gak masalah slama ini. nah kemaren itu aq install radius+ LAMP + chillispot dan hasilnya masih belum OK tapi yang jadi masalah adalah
- Chillispot itu melakukan Tunneling dan maskering DNS

ini menyebabkan ip forwading aq ikut berhenti bekarja. tapi cukup sulit juga ngedeteksinya
awalnya ping ke server aja dak mau tapi bukan RTO. dah 2-3 kali aq restart server tetep gagal. akhirnya aq buang semua paket yang baru aj aq install dan hasilnya OK
ping bisa reply dan SSH pun bisa dipake.

nah terakhit IP forwading, kok diem aj gak ad tanda2 kehidupan.
lalu aq lakukan tcpdump, untuk mengetahui apa yang terjadi dan LOG kernel

hasilnya

root@ubuntu:~# ping 10.10.10.1
PING 10.10.10.1 (10.10.10.1) 56(84) bytes of data.

[5]+  Stopped                 ping 10.10.10.1
root@ubuntu:~# ping google.com
PING google.com (64.233.167.99) 56(84) bytes of data.
64 bytes from py-in-f99.google.com (64.233.167.99): icmp_seq=458 ttl=236 time=398 ms
64 bytes from py-in-f99.google.com (64.233.167.99): icmp_seq=459 ttl=236 time=370 ms
64 bytes from py-in-f99.google.com (64.233.167.99): icmp_seq=461 ttl=236 time=472 ms
64 bytes from py-in-f99.google.com (64.233.167.99): icmp_seq=462 ttl=236 time=342 ms

ini lah LOG nya

 tcpdump -i eth1
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth1, link-type EN10MB (Ethernet), capture size 96 bytes
14:19:21.961639 IP 192.168.3.3.netbios-ns > 192.168.3.255.netbios-ns: NBT UDP PACKET(137): QUERY; REQUEST; BROADCAST
14:19:21.961884 NBF Packet: Name Query, Name=WORKGROUP       NameType=0x1D (Master Browser)
14:19:22.117486 IP6 fe80::2e0:81ff:fe5a:4697.mdns > ff02::fb.mdns: 0[|domain]
14:19:22.117588 IP peroxide.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 255.3.168.192.in-addr.arpa. (44)
14:19:22.117716 IP6 fe80::2e0:81ff:fe5a:4696.mdns > ff02::fb.mdns: 0[|domain]
14:19:22.117795 IP peroxide.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 255.3.168.192.in-addr.arpa. (44)
14:19:22.269139 IP ubuntu.local > py-in-f99.google.com: ICMP echo request, id 53538, seq 295, length 64
14:19:22.961623 IP 192.168.3.3.netbios-ns > 192.168.3.255.netbios-ns: NBT UDP PACKET(137): QUERY; REQUEST; BROADCAST
14:19:22.961860 NBF Packet: Name Query, Name=WORKGROUP       NameType=0x1D (Master Browser)
14:19:23.127475 IP6 fe80::2e0:81ff:fe5a:4697.mdns > ff02::fb.mdns: 0[|domain]
14:19:23.127561 IP peroxide.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 255.3.168.192.in-addr.arpa. (44)
14:19:23.127689 IP6 fe80::2e0:81ff:fe5a:4696.mdns > ff02::fb.mdns: 0[|domain]
14:19:23.127764 IP peroxide.local.mdns > 224.0.0.251.mdns: 0 PTR (QM)? 255.3.168.192.in-addr.arpa. (44)
14:19:23.269153 IP ubuntu.local > py-in-f99.google.com: ICMP echo request, id 53538, seq 296, length 64
14:19:23.961688 IP 192.168.3.3.netbios-ns > 192.168.3.255.netbios-ns: NBT UDP PACKET(137): QUERY; REQUEST; BROADCAST
14:19:23.961928

tail /var/log/messages
Feb 19 14:14:03 peroxide kernel: [16501.427473] device eth0 entered promiscuous mode
Feb 19 14:14:03 peroxide kernel: [16501.427489] audit(1203405243.757:4): dev=eth0 prom=256 old_prom=0 auid=4294967295
Feb 19 14:15:02 peroxide kernel: [16559.663523] device eth1 entered promiscuous mode
Feb 19 14:15:02 peroxide kernel: [16559.663539] audit(1203405302.037:5): dev=eth1 prom=256 old_prom=0 auid=4294967295
Feb 19 14:15:54 peroxide kernel: [16612.483652] device eth1 left promiscuous mode
Feb 19 14:15:54 peroxide kernel: [16612.483666] audit(1203405354.897:6): dev=eth1 prom=0 old_prom=256 auid=4294967295
Feb 19 14:19:21 peroxide kernel: [16825.668730] device eth1 entered promiscuous mode


nah solusinya ternyata cuma sepele

oxide:~$sudo  echo 1 > /proc/sys/net/ipv4/ip_forward


saya gak bisa pastiin, nilai ini berubah karena restart ato karena faktor yang aq sebutkan tadi, tapi yang jelas terakhir aq lihat nilainya adalah 0 (nol)