Contabo VPS 运行 Ubuntu 22.04 服务器，没有正在firewalld运行ufw，fail2ban已经安装并配置好但目前已停止以弄清楚发生了什么。
我有一个nc -4 -k -l -v 173.212.xxx.xxx 1026进程正在运行并监听端口 1026。173.212.xxx.xxx这是 VPS 的公共 IP，可以从外部访问（例如，端口 22、80 和 443 可以正常工作）。
由于某种原因，我无法连接到173.212.xxx.xxx:1026，连接总是超时。但 SSH 和 HTTP/HTTPS 并非如此。我想知道为什么我无法连接到其他端口，尽管它们正在被监听，并且它们显示如下nmap：
$ sudo nmap 173.212.xxx.xxx
Starting Nmap 7.80 ( https://nmap.org ) at 2022-12-21 16:11 CET
Nmap scan report for vmdxxx.contaboserver.net (173.212.xxx.xxx)
Host is up (0.0000090s latency).
Not shown: 988 closed ports
PORT STATE SERVICE
22/tcp open ssh
25/tcp open smtp
80/tcp open http
110/tcp open pop3
143/tcp open imap
443/tcp open https
587/tcp open submission
993/tcp open imaps
995/tcp open pop3s
1026/tcp open LSA-or-nterm # <-- not working
8088/tcp open radan-http # <-- Janus WebRTC server timing out as well (what I actually try to set up)
8089/tcp open unknown
$ sudo iptables -L
Chain INPUT (policy DROP)
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT all -- anywhere anywhere
ACCEPT icmp -- anywhere anywhere icmp echo-request
ACCEPT tcp -- anywhere anywhere tcp dpt:ssh
ACCEPT tcp -- anywhere anywhere tcp dpt:http
ACCEPT tcp -- anywhere anywhere tcp dpt:https
ACCEPT tcp -- anywhere anywhere tcp dpt:smtp
ACCEPT tcp -- anywhere anywhere tcp dpt:submission
ACCEPT tcp -- anywhere anywhere tcp dpt:pop3
ACCEPT tcp -- anywhere anywhere tcp dpt:pop3s
ACCEPT tcp -- anywhere anywhere tcp dpt:imap2
ACCEPT tcp -- anywhere anywhere tcp dpt:imaps
Chain FORWARD (policy DROP)
target prot opt source destination
DOCKER-USER all -- anywhere anywhere
DOCKER-ISOLATION-STAGE-1 all -- anywhere anywhere
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
DOCKER all -- anywhere anywhere
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain DOCKER (1 references)
target prot opt source destination
Chain DOCKER-ISOLATION-STAGE-1 (1 references)
target prot opt source destination
DOCKER-ISOLATION-STAGE-2 all -- anywhere anywhere
RETURN all -- anywhere anywhere
Chain DOCKER-ISOLATION-STAGE-2 (1 references)
target prot opt source destination
DROP all -- anywhere anywhere
RETURN all -- anywhere anywhere
Chain DOCKER-USER (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere
$ sudo netstat -tulpn
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 0.0.0.0:587 0.0.0.0:* LISTEN 988/master
tcp 0 0 173.212.xxx.xxx:1026 0.0.0.0:* LISTEN 38682/nc
tcp 0 0 0.0.0.0:995 0.0.0.0:* LISTEN 652/dovecot
tcp 0 0 0.0.0.0:993 0.0.0.0:* LISTEN 652/dovecot
tcp 0 0 0.0.0.0:110 0.0.0.0:* LISTEN 652/dovecot
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 747/sshd: /usr/sbin
tcp 0 0 0.0.0.0:25 0.0.0.0:* LISTEN 988/master
tcp 0 0 0.0.0.0:143 0.0.0.0:* LISTEN 652/dovecot
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 913/mysqld
tcp 0 0 127.0.0.1:33060 0.0.0.0:* LISTEN 913/mysqld
tcp 0 0 127.0.0.1:24 0.0.0.0:* LISTEN 652/dovecot
tcp 0 0 127.0.0.1:4190 0.0.0.0:* LISTEN 652/dovecot
tcp 0 0 127.0.0.1:9998 0.0.0.0:* LISTEN 39690/amavisd-new (
tcp 0 0 127.0.0.1:10024 0.0.0.0:* LISTEN 39690/amavisd-new (
tcp 0 0 127.0.0.1:10025 0.0.0.0:* LISTEN 988/master
tcp 0 0 127.0.0.1:10026 0.0.0.0:* LISTEN 39690/amavisd-new (
tcp 0 0 127.0.0.53:53 0.0.0.0:* LISTEN 623/systemd-resolve
tcp 0 0 173.212.xxx.xxx:8188 0.0.0.0:* LISTEN 36225/janus
tcp6 0 0 :::587 :::* LISTEN 988/master
tcp6 0 0 :::995 :::* LISTEN 652/dovecot
tcp6 0 0 :::993 :::* LISTEN 652/dovecot
tcp6 0 0 :::110 :::* LISTEN 652/dovecot
tcp6 0 0 :::80 :::* LISTEN 940/apache2
tcp6 0 0 :::22 :::* LISTEN 747/sshd: /usr/sbin
tcp6 0 0 :::25 :::* LISTEN 988/master
tcp6 0 0 :::143 :::* LISTEN 652/dovecot
tcp6 0 0 :::443 :::* LISTEN 940/apache2
tcp6 0 0 :::8089 :::* LISTEN 36225/janus
tcp6 0 0 :::8088 :::* LISTEN 36225/janus
udp 0 0 127.0.0.53:53 0.0.0.0:* 623/systemd-resolve
udp6 0 0 :::5002 :::* 36225/janus
udp6 0 0 :::5004 :::* 36225/janus
udp6 0 0 :::5102 :::* 36225/janus
udp6 0 0 :::5104 :::* 36225/janus
udp6 0 0 :::5106 :::* 36225/janus
我可以连接到端口1026，localhost但不能连接到远程主机。但为什么呢？我显然忽略了一些东西。有谁知道为什么所有端口都被从外部阻止了，即在哪里可以配置它？除了fail2ban几年前的设置之外，我不记得任何事情了。顺便说一句，我是个网络菜鸟。感谢您抽出时间！非常感谢您的帮助。