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软件更新后，网站无法访问

tag-icon • tag-icon 13.04 networking firewall iptables
软件更新后，网站无法访问

我今天早上刚刚应用了一堆推荐的更新（似乎将内核升级到了 3.8.0-32.47），突然间我无法通过端口 80（http）或 22（ssh）连接到计算机。Ping 仍然有效。此外，我的 syslog 和 kern.log 中充满了类似这样的消息

Oct 22 10:43:27 mu kernel: [ 4041.036862] Inbound IN=eth0 OUT= MAC=6c:62:6d:c8:b0:d3:18:03:73:34:81:b8:08:00 SRC=192.168.212.43 DST=192.168.212.56 LEN=48 TOS=0x00 PREC=0x00 TTL=128 ID=17389 DF PROTO=TCP SPT=59502 DPT=80 WINDOW=8192 RES=0x00 SYN URGP=0

我可以本地连接到 Web 服务器，所以对我来说这像是防火墙问题。我尝试过：

  • 从 GUFW 内部执行“重置防火墙”
  • 从命令行执行“sudo ufw allow 80”和“sudo ufw allow 22”

但这样不起作用。所以我去查看了“sudo iptables -L”，我得到了这个，但我不明白输出是什么（我用“example.com”隐藏了我雇主的域名）

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     tcp  --  ad1.example.com  anywhere             tcpflags:! FIN,SYN,RST,ACK/SYN
ACCEPT     udp  --  ad1.example.com  anywhere            
ACCEPT     tcp  --  ad2.example.com  anywhere             tcpflags:! FIN,SYN,RST,ACK/SYN
ACCEPT     udp  --  ad2.example.com  anywhere            
ACCEPT     tcp  --  ad3.example.com  anywhere             tcpflags:! FIN,SYN,RST,ACK/SYN
ACCEPT     udp  --  ad3.example.com  anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     icmp --  anywhere             anywhere             limit: avg 10/sec burst 5
DROP       all  --  anywhere             255.255.255.255     
DROP       all  --  anywhere             192.168.212.255     
DROP       all  --  base-address.mcast.net/8  anywhere            
DROP       all  --  anywhere             base-address.mcast.net/8 
DROP       all  --  255.255.255.255      anywhere            
DROP       all  --  anywhere             0.0.0.0             
DROP       all  --  anywhere             anywhere             state INVALID
LSI        all  -f  anywhere             anywhere             limit: avg 10/min burst 5
INBOUND    all  --  anywhere             anywhere            
LOG_FILTER  all  --  anywhere             anywhere            
LOG        all  --  anywhere             anywhere             LOG level info prefix "Unknown Input"
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:http
ufw-before-logging-input  all  --  anywhere             anywhere            
ufw-before-input  all  --  anywhere             anywhere            
ufw-after-input  all  --  anywhere             anywhere            
ufw-after-logging-input  all  --  anywhere             anywhere            
ufw-reject-input  all  --  anywhere             anywhere            
ufw-track-input  all  --  anywhere             anywhere            
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:http

知道我做错了什么吗？或者如何解决它？（我想我即将学到很多有关 iptables 的知识。）

更新

不出所料，机器上的其他服务（MySQL）也没有响应。nmap 告诉我端口是开放的，

chris@mu:/var/log$ nmap 192.168.212.56

Starting Nmap 6.00 ( http://nmap.org ) at 2013-10-22 10:55 EDT
Nmap scan report for sentry (192.168.212.56)
Host is up (0.00030s latency).
Not shown: 993 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
111/tcp  open  rpcbind
139/tcp  open  netbios-ssn
445/tcp  open  microsoft-ds
3306/tcp open  mysql
5666/tcp open  nrpe

答案1

我终于找到了可以清除所有防火墙规则的命令sudo iptables -F（这是一台开发机，所以我不太在意），并使用了它。现在一切都可以访问了。

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