I am trying to open a port in Ubuntu 17.10, but first some background.
For the last 16 hours I've been working on getting a BBS mailer set up under dosbox. In my dosbox conf, I have set up "serial1=modem listenport:601" to listen on port 601. To test this, I was able to open a terminal and do "telnet localhost 601" and I could connect everytime. The moment I try to open the port in iptables and in ufw (I found out how from stack exchange) now the port seems to be closed and dosbox reports "Serial1: Modem could not open TCP port 601."
But this worked all day until I opened the ports.
Here is what iptables and ufw are reporting:
iptables -L | grep 601
ACCEPT tcp -- anywhere anywhere tcp dpt:601
ACCEPT udp -- anywhere anywhere udp dpt:601
ufw status Status: active
To Action From
-- ------ ----
601 ALLOW Anywhere
601 (v6) ALLOW Anywhere (v6)
So my question is two-fold:
1) why did this work before I opened the port but now won't work when the port is open? 2) How do I make it work?
My end goal is to be able to access the BBS mailer from outside my network, but for now I just need to test locally with ports open. (after this, my next step is to get a dynamic dns so I can begin testing from outside the network)