MySQL 的 3306 端口已关闭

Question

看来我的服务器上用于远程 MySQL 访问的端口 3306 已关闭。在 /etc/mysql/my.cnf 中，我已将 bind-address 设置更改为我的远程 IP，并重新启动了服务器。不过，对本地主机和我的远程 IP 进行 nmap 扫描显示，它仍然处于关闭状态，并且只能从本地主机访问：

root@an0n:/etc/mysql/conf.d# nmap REMOTEIP 

Starting Nmap 5.00 ( http://nmap.org ) at 2015-04-09 20:30 MSK
Interesting ports on DOMAIN (REMOTEIP):
Not shown: 995 closed ports
PORT    STATE SERVICE
22/tcp  open  ssh
53/tcp  open  domain
80/tcp  open  http
139/tcp open  netbios-ssn
445/tcp open  microsoft-ds

Nmap done: 1 IP address (1 host up) scanned in 0.17 seconds
root@an0n:/etc/mysql/conf.d# nmap localhost

Starting Nmap 5.00 ( http://nmap.org ) at 2015-04-09 20:30 MSK
Warning: Hostname localhost resolves to 2 IPs. Using 127.0.0.1.
Interesting ports on localhost.localdomain (127.0.0.1):
Not shown: 992 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
25/tcp   open  smtp
53/tcp   open  domain
80/tcp   open  http
139/tcp  open  netbios-ssn
445/tcp  open  microsoft-ds
587/tcp  open  submission
3306/tcp open  mysql

Nmap done: 1 IP address (1 host up) scanned in 0.12 seconds

我现在该在哪里搜索？顺便说一句，我从未使用过 iptables。