Setup:I have logged in to a Huawei router using ssh. It's a busybox system with ash. Tools available are ifconfig, iptables and some others.What I want to do:Making all ports (http, ssh, telnet, etc.) available to the internet.# iptables -L --line-numbersChain INPUT (policy ACCEPT)num  target     prot opt source               destination         1    REJECT     tcp  --  anywhere             anywhere            tcp dpt:113 reject-with tcp-reset 2    ACCEPT     all  --  anywhere             anywhere            3    INPUT_DOSFLT  all  --  anywhere             anywhere            4    INPUT_SERVICE_ACL  all  --  anywhere             anywhere            5    INPUT_URLFLT  all  --  anywhere             anywhere            6    INPUT_SERVICE  all  --  anywhere             anywhere            7    SPI_FILTER  all  --  anywhere             anywhere            8    INPUT_FIREWALL  all  --  anywhere             anywhere            Chain FORWARD (policy ACCEPT)num  target     prot opt source               destination         1    FWD_DOSFLT  all  --  anywhere             anywhere            2    FWD_MACFLT  all  --  anywhere             anywhere            3    FWD_URLFLT  all  --  anywhere             anywhere            4    FWD_IPFLT  all  --  anywhere             anywhere            5    FWD_NATSERVICE  all  --  anywhere             anywhere            6    FWD_SERVICE  all  --  anywhere             anywhere            7    SPI_FILTER  all  --  anywhere             anywhere            8    FWD_FIREWALL  all  --  anywhere             anywhere            Chain OUTPUT (policy ACCEPT)num  target     prot opt source               destination         1    SPI_FILTER  all  --  anywhere             anywhere            2    ACCEPT     all  --  anywhere             anywhere            3    OUTPUT_DOSFLT  all  --  anywhere             anywhere            Chain ACC_FLT (0 references)num  target     prot opt source               destination         Chain DMZ_FLT (1 references)num  target     prot opt source               destination         Chain FWD_DOSFLT (1 references)num  target     prot opt source               destination         1    syn_flood  tcp  --  anywhere             anywhere            tcp flags:FIN,SYN,RST,ACK/SYN 2    ping_flood  icmp --  anywhere             anywhere            icmp echo-request Chain FWD_FIREWALL (1 references)num  target     prot opt source               destination         Chain FWD_IPFLT (1 references)num  target     prot opt source               destination         Chain FWD_MACFLT (1 references)num  target     prot opt source               destination         Chain FWD_NATSERVICE (1 references)num  target     prot opt source               destination         1    PORTMAP_FLT  all  --  anywhere             anywhere            2    UPNP_PORTMAP  all  --  anywhere             anywhere            3    DMZ_FLT    all  --  anywhere             anywhere            Chain FWD_SERVICE (1 references)num  target     prot opt source               destination         1    ACCEPT     udp  --  anywhere             anywhere            multiport ports 53,67,68,80,443 2    ACCEPT     tcp  --  anywhere             anywhere            multiport ports 53,67,68,80,443 3    ACCEPT     udp  --  anywhere             anywhere            multiport ports 143,110,25 4    ACCEPT     tcp  --  anywhere             anywhere            multiport ports 143,110,25 5    ACCEPT     udp  --  anywhere             anywhere            multiport ports 21,115,23 6    ACCEPT     tcp  --  anywhere             anywhere            multiport ports 21,115,23 7    ACCEPT     icmp --  anywhere             anywhere            Chain FWD_URLFLT (1 references)num  target     prot opt source               destination         Chain FWFLT_NULL (0 references)num  target     prot opt source               destination         Chain INPUT_DOSFLT (1 references)num  target     prot opt source               destination         1    syn_flood  tcp  --  anywhere             anywhere            tcp flags:FIN,SYN,RST,ACK/SYN 2    ping_flood  icmp --  anywhere             anywhere            icmp echo-request Chain INPUT_FIREWALL (1 references)num  target     prot opt source               destination         1    DROP       all  --  anywhere             anywhere            2    DROP       tcp  --  anywhere             anywhere            tcp dpt:23 3    DROP       tcp  --  anywhere             anywhere            tcp dpt:8081 4    DROP       all  --  anywhere             anywhere            Chain INPUT_SERVICE (1 references)num  target     prot opt source               destination         1    ACCEPT     udp  --  anywhere             anywhere            multiport ports 53,67,68 2    DROP       tcp  --  anywhere             anywhere            multiport dports 631 3    DROP       tcp  --  anywhere             anywhere            tcp flags:FIN,SYN,ACK/SYN 4    ACCEPT     udp  --  anywhere             anywhere            udp dpt:500 5    ACCEPT     udp  --  anywhere             anywhere            udp dpt:4500 6    ACCEPT     esp  --  anywhere             anywhere            7    ACCEPT     udp  --  anywhere             anywhere            udp dpts:67:68 8    ACCEPT     udp  --  anywhere             anywhere            udp dpt:6050 9    ACCEPT     udp  --  anywhere             anywhere            udp dpt:0 10   ACCEPT     udp  --  anywhere             anywhere            udp dpts:50000:50020 Chain INPUT_SERVICE_ACL (1 references)num  target     prot opt source               destination         1    ACCEPT     all  --  anywhere             anywhere            2    ACCEPT     icmp --  anywhere             anywhere            Chain INPUT_URLFLT (1 references)num  target     prot opt source               destination         1    ACCEPT     udp  --  anywhere             anywhere            udp dpt:53 dns_flt match homerouter.cpe Chain IPFLT_BLACKTABLE (0 references)num  target     prot opt source               destination         Chain IPFLT_WHITETABLE (0 references)num  target     prot opt source               destination         Chain MACFLT_BLACKTABLE (0 references)num  target     prot opt source               destination         Chain MACFLT_WHITETABLE (0 references)num  target     prot opt source               destination         Chain OUTPUT_DOSFLT (1 references)num  target     prot opt source               destination         Chain PORTMAP_FLT (1 references)num  target     prot opt source               destination         1    ACCEPT     tcp  --  anywhere             192.168.1.2         tcp dpt:22 Chain SPI_FILTER (3 references)num  target     prot opt source               destination         1    DROP       all  --  anywhere             anywhere            state INVALID 2    ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED Chain UPNP_PORTMAP (1 references)num  target     prot opt source               destination         Chain URLFLT_BLACKTABLE (0 references)num  target     prot opt source               destination         Chain URLFLT_WHITETABLE (0 references)num  target     prot opt source               destination         Chain ping_flood (2 references)num  target     prot opt source               destination         1    RETURN     all  --  anywhere             anywhere            limit: avg 100/sec burst 150 2    DROP       all  --  anywhere             anywhere            Chain syn_flood (2 references)num  target     prot opt source               destination         1    RETURN     all  --  anywhere             anywhere            limit: avg 100/sec burst 150 2    DROP       all  --  anywhere             anywhere 
Make home router accessible via Internet
iptables;internet;busybox;router