Добавил в конфиг:
127.0.0.1 127 192.168.0.1 192
Запустил tcpdump и telnet:
$ telnet 127.0.0.1 127
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
Connection closed by foreign host.
# tcpdump -i any -n port 127 or port 192
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on any, link-type LINUX_SLL (Linux cooked), capture size 65535 bytes
12:42:40.869870 IP 127.0.0.1.42205 > 127.0.0.1.127: Flags [S], seq 3890575008, win 32792, options [mss 16396,sackOK,TS val 86107963 ecr 0,nop,wscale 7], length 0
12:42:40.869882 IP 127.0.0.1.127 > 127.0.0.1.42205: Flags [S.], seq 293205897, ack 3890575009, win 32768, options [mss 16396,sackOK,TS val 86107963 ecr 86107963,nop,wscale 7], length 0
12:42:40.869891 IP 127.0.0.1.42205 > 127.0.0.1.127: Flags [.], ack 1, win 257, options [nop,nop,TS val 86107963 ecr 86107963], length 0
12:42:40.869959 IP 192.168.0.1.36533 > 192.168.0.1.192: Flags [S], seq 3984613777, win 32792, options [mss 16396,sackOK,TS val 86107963 ecr 0,nop,wscale 7], length 0
12:42:40.869967 IP 192.168.0.1.192 > 192.168.0.1.36533: Flags [R.], seq 0, ack 3984613778, win 0, length 0
12:42:40.870023 IP 127.0.0.1.127 > 127.0.0.1.42205: Flags [F.], seq 1, ack 1, win 256, options [nop,nop,TS val 86107963 ecr 86107963], length 0
12:42:40.870071 IP 127.0.0.1.42205 > 127.0.0.1.127: Flags [F.], seq 1, ack 2, win 257, options [nop,nop,TS val 86107963 ecr 86107963], length 0
12:42:40.870085 IP 127.0.0.1.127 > 127.0.0.1.42205: Flags [.], ack 2, win 256, options [nop,nop,TS val 86107963 ecr 86107963], length 0
Видно, что на порт 192 идут пакеты от 192.168.0.1, т.е. адрес 127.0.0.1 не светится.