My tiny office has 1 router, which is connected to ADSL line on one end and my laptop on other end. In office, laptop’s local IP is 192.168.1.2.
On office router, I have setup port (22) forwarding for SSH access. I also have DuckDNS script that allows me to ssh -v -t -L 5900:localhost:5900 myname.duckdns.org into my office laptop whenever I want.
I followed the same port-forwarding procedure to configure my router to forward Port 8082 to 192.168.1.2 (TCP, WAN interface is pppoe2). I ran a python/nodejs http server listening on 0.0.0.0:8082.
If I try to access my newly spun server from public IP I get timeout. This is the problem. I can SSH into my remote machine, but website hosted on it doesn’t work
Steps tried:
I take remote desktop of office laptop (using port 5900 for x11 forwarding) and find that firefox can open localhost:8082, 127.0.0.1:8082 and 192.168.1.2:8082 properly.
I tried shutting down extra services like gogs and nginx (which was listening on port 80 even though I didn’t tell it to) via systemctl, but still no luck.
Further, curl http://PUBLIC_IP:8082 gives different outputs:
- At home, in my Cmder I get
curl: (7) Failed to connect to PUBLIC_IP port 8082: Timed out
- However, in SSH terminal (i.e. of remote machine), I get
curl: (7) Failed to connect to PUBLIC_IP port 8082: Connection refused
Why is connection refused?
Thanks to @davidgo, I tried
$ sudo tcpdump -vv -i enp7s0 | grep 8082 tcpdump: listening on enp7s0, link-type EN10MB (Ethernet), capture size 262144 bytes
If I curl localhost:8082 or 192.168.1.2:8082 I see 200 on server logs but I don’t see any output in the above command.
But if I curl PUBLIC_IP:8082 from
- inside SSH session I get
duckDNSsubDomain.40626 > abts-north-dynamic-031.P3.P2.P1.airtelbroadband.in.8082: Flags [S], cksum 0x469a (incorrect -> 0x84f5), seq 18095393, win 64240, options [mss 1460,sackOK,TS val 2474578357 ecr 0,nop,wscale 7], length 0 abts-north-dynamic-031.P3.P2.P1.airtelbroadband.in.8082 > duckDNSsubDomain.40626: Flags [R.], cksum 0x8cea (correct), seq 0, ack 18095394, win 0, length 0
and a quick connection refused complain by curl (BTW my public IPv4 looks like P1.P2.P3.31.
- And if I do the same curl from my home computer I see
157.32.251.70.50664 > duckDNSsubDomain.8082: Flags [S], cksum 0x299d (correct), seq 132055921, win 64240, options [mss 1370,nop,wscale 8,nop,nop,sackOK], length 0 157.32.251.70.50664 > duckDNSsubDomain.8082: Flags [S], cksum 0x299d (correct), seq 132055921, win 64240, options [mss 1370,nop,wscale 8,nop,nop,sackOK], length 0 157.32.251.70.50664 > duckDNSsubDomain.8082: Flags [S], cksum 0x299d (correct), seq 132055921, win 64240, options [mss 1370,nop,wscale 8,nop,nop,sackOK], length 0 157.32.251.70.50664 > duckDNSsubDomain.8082: Flags [S], cksum 0x299d (correct), seq 132055921, win 64240, options [mss 1370,nop,wscale 8,nop,nop,sackOK], length 0 157.32.251.70.50664 > duckDNSsubDomain.8082: Flags [S], cksum 0x299d (correct), seq 132055921, win 64240, options [mss 1370,nop,wscale 8,nop,nop,sackOK], length 0
and curl fails with timeout.
Now I am guessing my ISP doesn’t like random ports. So I tried hosting my webserver on port 80. Again, localhost and 192.186.1.2 work as expected but http://PUBLIC_IP:80/ opens up router control panel 🙁
So I try hosting it on a well-known port that’s not 80 or 443. I choose 21 (FTP), use sudo to run webserver listening on 0.0.0.0:21 but firefox/chrome don’t let me open it and curl hangs for a while before failing with a timeout.
