@simos Thanks a lot for your reply.
-> Recreating container, no ip is set
lxc launch ubuntu:20.04 mycontainer
Creating mycontainer
Starting mycontainer
lxc list
+-------------+---------+------+------+-----------+-----------+
| NAME | STATE | IPV4 | IPV6 | TYPE | SNAPSHOTS |
+-------------+---------+------+------+-----------+-----------+
| mycontainer | RUNNING | | | CONTAINER | 0 |
+-------------+---------+------+------+-----------+-----------+
| test | RUNNING | | | CONTAINER | 0 |
+-------------+---------+------+------+-----------+-----------+
-> I was unable to find any other DHCP server and there is no dhcpd daemon running (ps aux | grep dhcpd)
-> Please find below my iptables, I did the test also adding in/out/fwd accept all rules, but the result is the same.
sudo iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
f2b-sshd tcp -- anywhere anywhere multiport dports ssh
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
DROP all -- 127.0.0.0/8 anywhere
ACCEPT icmp -- anywhere anywhere icmp echo-reply ctstate NEW
ACCEPT icmp -- anywhere anywhere icmp destination-unreachable ctstate NEW
ACCEPT icmp -- anywhere anywhere icmp time-exceeded ctstate NEW
ACCEPT icmp -- anywhere anywhere icmp parameter-problem ctstate NEW
ICMPFLOOD icmp -- anywhere anywhere icmp echo-request ctstate NEW
PORTSCAN tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,PSH,ACK,URG/NONE
PORTSCAN tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,PSH,ACK,URG/FIN
PORTSCAN tcp -- anywhere anywhere tcp flags:FIN,SYN/FIN,SYN
PORTSCAN tcp -- anywhere anywhere tcp flags:SYN,RST/SYN,RST
PORTSCAN tcp -- anywhere anywhere tcp flags:FIN,RST/FIN,RST
PORTSCAN tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,PSH,ACK,URG/FIN,PSH,URG
PORTSCAN tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,PSH,ACK,URG/FIN,SYN,RST,PSH,ACK,URG
PORTSCAN tcp -- anywhere anywhere tcp flags:FIN,SYN,RST,PSH,ACK,URG/FIN,SYN,RST,PSH,ACK,URG
PORTSCAN tcp -- anywhere anywhere tcp flags:FIN,ACK/FIN
PORTSCAN tcp -- anywhere anywhere tcp flags:PSH,ACK/PSH
PORTSCAN tcp -- anywhere anywhere tcp flags:ACK,URG/URG
DROP all -- anywhere anywhere ADDRTYPE match dst-type BROADCAST
DROP all -- anywhere anywhere ADDRTYPE match dst-type MULTICAST
DROP all -- anywhere base-address.mcast.net/4
DROP all -- anywhere anywhere ADDRTYPE match dst-type ANYCAST
ACCEPT all -- 102.53.11.160 anywhere
SSHBRUTE tcp -- anywhere anywhere tcp dpt:ssh ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:12227 ctstate NEW
ACCEPT tcp -- anywhere anywhere tcp dpt:5000 ctstate NEW
DROP all -- anywhere anywhere
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain SSHBRUTE (1 references)
target prot opt source destination
all -- anywhere anywhere recent: SET name: SSH side: source mask: 255.255.255.255
DROP all -- anywhere anywhere recent: UPDATE seconds: 60 hit_count: 10 name: SSH side: source mask: 255.255.255.255
ACCEPT all -- anywhere anywhere
Chain ICMPFLOOD (1 references)
target prot opt source destination
all -- anywhere anywhere recent: SET name: ICMP side: source mask: 255.255.255.255
DROP all -- anywhere anywhere recent: UPDATE seconds: 1 hit_count: 5 TTL-Match name: ICMP side: source mask: 255.255.255.255
ACCEPT all -- anywhere anywhere
Chain PORTSCAN (11 references)
target prot opt source destination
DROP all -- anywhere anywhere
Chain f2b-sshd (1 references)
target prot opt source destination
REJECT all -- 221.181.185.29 anywhere reject-with icmp-port-unreachable
RETURN all -- anywhere anywhere
Edit: