Router Web Server WAN Access

Question

I have a ISP supplied D-Link router running a customized firmware. I am trying to enable access to router's web server on WAN. While the router does give this option under TCP/IP Settings > WAN Interface, the setting does not seem to work as I am unable to access the web server using my public IP.

Surprisingly, other features like enabling ICMP or SAMBA on WAN works. The latter when enabled opens ports 445 and 139 on WAN. The iptables entries are as below: (Of course, IPs are changed.)

#iptables -nL -v --line-numbers

Chain INPUT (policy DROP 18 packets, 2447 bytes)
num   pkts bytes target     prot opt in     out     source               destination
1      128 17459 ACCEPT     all  --  *      *       0.0.0.0/0            0.0.0.0/0           state RELATED,ESTABLISHED
2        0     0 ACCEPT     tcp  --  ppp0   *       0.0.0.0/0            86.96.111.32        tcp dpt:80
3        0     0 ACCEPT     tcp  --  eth1   *       0.0.0.0/0            10.137.158.217      tcp dpt:80
4        0     0 DROP       udp  --  ppp0   *       0.0.0.0/0            86.96.111.32        udp dpt:1900
5        0     0 ACCEPT     tcp  --  eth1   *       0.0.0.0/0            10.137.158.217      tcp dpt:!80
6        0     0 ACCEPT     udp  --  eth1   *       0.0.0.0/0            10.137.158.217      udp dpt:!1900
7        0     0 DROP       icmp --  ppp0   *       0.0.0.0/0            86.96.111.32        icmp type 8
8        0     0 ACCEPT     2    --  ppp0   *       0.0.0.0/0            0.0.0.0/0
9      133 17435 ACCEPT     all  --  br0    *       0.0.0.0/0            0.0.0.0/0
10       0     0 ACCEPT     all  --  lo     *       0.0.0.0/0            0.0.0.0/0
11       0     0 ACCEPT     tcp  --  ppp0   *       0.0.0.0/0            86.96.111.32        tcp dpt:51005

Chain FORWARD (policy DROP 0 packets, 0 bytes)
num   pkts bytes target     prot opt in     out     source               destination
1       39  2128 TCPMSS     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           tcp flags:0x06/0x02 TCPMSS clamp to PMTU
2        0     0 ACCEPT     udp  --  *      *       0.0.0.0/0            0.0.0.0/0           udp spt:1701
3        0     0 ACCEPT     udp  --  *      *       0.0.0.0/0            0.0.0.0/0           udp dpt:1701
4        0     0 ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           tcp dpt:1723
5        0     0 ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0           tcp spt:1723
6        0     0 ACCEPT     47   --  *      *       0.0.0.0/0            0.0.0.0/0
7        0     0 ACCEPT     udp  --  eth1   *       0.0.0.0/0            224.0.0.0/4         udp
8      646 47785 ACCEPT     all  --  br0    *       0.0.0.0/0            0.0.0.0/0
9        0     0 ACCEPT     udp  --  ppp0   br0     0.0.0.0/0            0.0.0.0/0           udp dpt:500
10       0     0 ACCEPT     udp  --  ppp0   *       0.0.0.0/0            224.0.0.0/4         udp
11       0     0 ACCEPT     esp  --  ppp0   br0     0.0.0.0/0            0.0.0.0/0
12     823 1055K ACCEPT     all  --  ppp0   *       0.0.0.0/0            0.0.0.0/0           state RELATED,ESTABLISHED
13       0     0 MINIUPNPD  all  --  ppp0   !ppp0   0.0.0.0/0            0.0.0.0/0

Chain OUTPUT (policy ACCEPT 211 packets, 61932 bytes)
num   pkts bytes target     prot opt in     out     source               destination

Chain MINIUPNPD (1 references)
num   pkts bytes target     prot opt in     out     source               destination

When "web server access on WAN" option is unchecked, rule #2 from INPUT chain above changes to DROP which implies it does work, but for some reason I am unable to reach the web server from WAN. Please suggest ideas.

Answer 1

Alright! So if anybody faces the same issue as myself, this is for them.

It was my ISP blocking port 80 and 23 on WAN interface. When I changed the ports, it worked like a charm!