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Galdona

Member

Registered: 2006-03-15

Posts: 196

should it be eth0 or ppp0 when masquerading [solved]

edit: sorry, the answer is ppp0. i was using eth0, and this is what has been causing me a lot of frustration.

when Im going to do masquerading through iptables, and Im using pppoe (adsl), should my internet connection be referenced as eth0 or ppp0?

im trying to follow a tutorial about masquerading, but i dont know what to use. i think adsl is a kind of pseudo-dial-up:

from the tutorial:

Assuming external internet card is eth0, and external IP is 123.12.23.43 and the internal network card is eth1, then:

$> modprobe ipt_MASQUERADE # If this fails, try continuing anyway
$> iptables -F; iptables -t nat -F; iptables -t mangle -F
$> iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to 123.12.23.43
$> echo 1 > /proc/sys/net/ipv4/ip_forward

Or for a dial-up connection:

$> modprobe ipt_MASQUERADE # If this fails, try continuing anyway
$> iptables -F; iptables -t nat -F; iptables -t mangle -F
$> iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE
$> echo 1 > /proc/sys/net/ipv4/ip_forward

this is my ifconfig output:

# ifconfig
eth0      Link encap:Ethernet  HWaddr 00:C0:26:7B:5C:83
          inet6 addr: fe80::2c0:26ff:fe7b:5c83/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:3407 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3609 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2297030 (2.1 Mb)  TX bytes:617705 (603.2 Kb)
          Interrupt:11 Base address:0xc000

eth1      Link encap:Ethernet  HWaddr 00:E0:4C:C9:F0:53
          inet addr:192.168.0.1  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::2e0:4cff:fec9:f053/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 b)  TX bytes:468 (468.0 b)
          Interrupt:10 Base address:0xe000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

ppp0      Link encap:Point-to-Point Protocol
          inet addr:58.96.112.48 P-t-P:210.5.96.254  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
          RX packets:3123 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3321 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:2209131 (2.1 Mb)  TX bytes:527164 (514.8 Kb)