你猜？
以totolink T10为例：
# ifconfig
br0 Link encap:Ethernet HWaddr F4:28:53:DC:96:58
inet addr:192.168.55.1 Bcast:192.168.55.255 Mask:255.255.255.0
inet6 addr: fe80::f628:53ff:fedc:9658/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:5387 errors:0 dropped:0 overruns:0 frame:0
TX packets:4135 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2178275 (2.0 MiB) TX bytes:2756549 (2.6 MiB)
br0:1 Link encap:Ethernet HWaddr F4:28:53:DC:96:58
inet addr:10.188.188.188 Bcast:10.255.255.255 Mask:255.255.255.255
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
eth0 Link encap:Ethernet HWaddr F4:28:53:DC:96:58
inet6 addr: fe80::f628:53ff:fedc:9658/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 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)
Interrupt:4
eth1 Link encap:Ethernet HWaddr F4:28:53:DC:96:59
inet addr:192.168.0.108 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::f628:53ff:fedc:9659/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:11854 errors:0 dropped:0 overruns:0 frame:0
TX packets:6782 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:6996943 (6.6 MiB) TX bytes:998271 (974.8 KiB)
Interrupt:4
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:65536 Metric:1
RX packets:138 errors:0 dropped:0 overruns:0 frame:0
TX packets:138 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:9945 (9.7 KiB) TX bytes:9945 (9.7 KiB)
wlan0 Link encap:Ethernet HWaddr F4:28:53:DC:96:58
inet6 addr: fe80::f628:53ff:fedc:9658/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:7625 errors:0 dropped:0 overruns:0 frame:0
TX packets:8650 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:3136430 (2.9 MiB) TX bytes:7084982 (6.7 MiB)
Interrupt:5
wlan1 Link encap:Ethernet HWaddr F4:28:53:DC:96:5C
inet6 addr: fe80::f628:53ff:fedc:965c/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:14435 errors:0 dropped:0 overruns:0 frame:0
TX packets:242 errors:1 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2897769 (2.7 MiB) TX bytes:43590 (42.5 KiB)
Interrupt:6
# ./busybox-mipsel netstat -pantu
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN 1395/lighttpd
tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1395/lighttpd
tcp 0 0 0.0.0.0:53 0.0.0.0:* LISTEN 7242/dnsmasq
tcp 0 0 0.0.0.0:1883 0.0.0.0:* LISTEN 1375/cs_broker
tcp 0 0 192.168.0.108:49138 120.24.109.166:9090 ESTABLISHED 7224/crpc
tcp 0 0 127.0.0.1:58225 127.0.0.1:1883 ESTABLISHED 1376/cste_sub
tcp 0 0 127.0.0.1:1883 127.0.0.1:58225 ESTABLISHED 1375/cs_broker
tcp 0 0 :::53 :::* LISTEN 7242/dnsmasq
tcp 0 0 :::23 :::* LISTEN 887/telnetd
tcp 0 0 :::1883 :::* LISTEN 1375/cs_broker
tcp 0 378 ::ffff:192.168.55.1:23 ::ffff:192.168.55.2:54033 ESTABLISHED 887/telnetd
udp 0 0 0.0.0.0:53 0.0.0.0:* 7242/dnsmasq
udp 0 0 0.0.0.0:67 0.0.0.0:* 1091/udhcpd
udp 0 0 0.0.0.0:9034 0.0.0.0:* 882/UDPserver
udp 0 0 :::53 :::* 7242/dnsmasq
#
# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default localhost 0.0.0.0 UG 0 0 0 eth1
192.168.0.0 * 255.255.255.0 U 0 0 0 eth1
192.168.0.1 localhost 255.255.255.255 UGH 0 0 0 eth1
192.168.1.1 localhost 255.255.255.255 UGH 0 0 0 eth1
192.168.55.0 * 255.255.255.0 U 0 0 0 br0
# iptables -nvL
Chain PREROUTING (policy ACCEPT 2596 packets, 1341K bytes)
pkts bytes target prot opt in out source destination
Chain INPUT (policy DROP 70 packets, 21278 bytes)
pkts bytes target prot opt in out source destination
442 31181 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 DROP tcp -- eth1 * 0.0.0.0/0 192.168.0.108 tcp dpt:80
0 0 DROP udp -- eth1 * 0.0.0.0/0 192.168.0.108 udp dpt:1900
1 576 ACCEPT udp -- eth1 * 0.0.0.0/0 0.0.0.0/0 udp dpt:68
0 0 DROP icmp -- eth1 * 0.0.0.0/0 192.168.0.108 icmp type 8
12 432 ACCEPT 2 -- eth1 * 0.0.0.0/0 0.0.0.0/0
67 10242 ACCEPT all -- br0 * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- eth0 * 0.0.0.0/0 0.0.0.0/0
5 321 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT 2 -- * * 0.0.0.0/0 0.0.0.0/0
Chain FORWARD (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
202 12548 TCPMSS tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp flags:0x06/0x02 TCPMSS
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp spt:1701
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:1701
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:1723
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp spt:1723
0 0 ACCEPT 47 -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT udp -- eth1 * 0.0.0.0/0 224.0.0.0/4 udp
0 0 ACCEPT 114 -- eth1 * 0.0.0.0/0 224.0.0.0/4
1 52 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 state INVALID
907 108K ACCEPT all -- br0 * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT udp -- eth1 br0 0.0.0.0/0 0.0.0.0/0 udp dpt:500
1077 1167K ACCEPT all -- eth1 * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT udp -- eth1 * 0.0.0.0/0 224.0.0.0/4 udp
0 0 ACCEPT esp -- eth1 br0 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- eth1 * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
Chain OUTPUT (policy ACCEPT 343 packets, 355K bytes)
pkts bytes target prot opt in out source destination
# ./busybox-mipsel nc -vvv -l -u -p 68
listening on [::]:68 ...
connect to 192.168.0.108:68 from localhost:46744 ([::ffff:192.168.0.113]:46744)
hello
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