§ LAN troubleshooting

§ General set-up

• ALICE = private IP of main desktop
• BOB = private IP of netbook, with sshd confirmed up and running, eee.lan shown with that IP in OpenWrt's Overview page
• OpenWrt's Firewall Summary page (like iptables -L, I believe)

1217 0 jj@ALICE:~$ nmap BOB
Starting Nmap 7.80 ( https://nmap.org ) at 2020-09-18 17:13 BST
Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn
Nmap done: 1 IP address (0 hosts up) scanned in 3.07 seconds

1218 0 jj@ALICE:~$ nmap -Pn BOB
Starting Nmap 7.80 ( https://nmap.org ) at 2020-09-18 17:14 BST
Nmap scan report for eee.lan (BOB)
Host is up.
All 1000 scanned ports on eee.lan (BOB) are filtered

Nmap done: 1 IP address (1 host up) scanned in 201.40 seconds

1219 0 jj@ALICE:~$ telnet BOB 22
Trying BOB...
^C

1220 130 jj@ALICE:~$ ping BOB
PING BOB (BOB) 56(84) bytes of data.
64 bytes from BOB: icmp_seq=1 ttl=64 time=13.2 ms
64 bytes from BOB: icmp_seq=2 ttl=64 time=1.49 ms
^C
--- BOB ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 1.493/7.355/13.218/5.862 ms

1221 0 jj@ALICE:~$ 

§ Next...

• OpenWrt docs say it doesn't filter by default, but...
• It seems to be, so I need to read up on iptables and tackle that wall of text that is the firewall rules
• Figure out logging on the router, to make future troubleshooting easier
• Apply this new knowledge to the ufw instance on my desktop...
• Right now, I can bridge LXD containers to my LAN, but only when ufw is disabled
• I'm thinking I should be able to write some rules in a before file to allow bridging traffic, but, again, my f/w-fu is weak at the mo