我正在使用 ubuntu 服务器,现在我正在尝试使用以下命令启用防火墙:
ufw default deny incoming
ufw default allow outgoing
ufw allow ssh
ufw allow www
ufw allow https
ufw enable
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我也试过做ufw default deny incoming最后一个,但仍然没有运气,当我启用防火墙时,它会在我将默认设置为拒绝时阻止所有内容,但是当我将其设置为允许时,它运行良好,就像规则被忽略一样。是什么原因造成的?
这是我的输出,iptables -L -v -n
我也尝试了建议的解决方案,但仍然没有运气,只有当我成功时它才能正常工作default allow incoming
Chain INPUT (policy DROP 30 packets, 1764 bytes)
pkts bytes target prot opt in out source destination
Chain FORWARD (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 2 packets, 104 bytes)
pkts bytes target prot opt in out source destination
Chain ufw-after-forward (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-after-input (0 references)
pkts bytes target prot opt in out source destination
0 0 ufw-skip-to-policy-input udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:137
0 0 ufw-skip-to-policy-input udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:138
0 0 ufw-skip-to-policy-input tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:139
0 0 ufw-skip-to-policy-input tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:445
0 0 ufw-skip-to-policy-input udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:67
0 0 ufw-skip-to-policy-input udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:68
0 0 ufw-skip-to-policy-input all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type BROADCAST
Chain ufw-after-logging-forward (0 references)
pkts bytes target prot opt in out source destination
0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW BLOCK] "
Chain ufw-after-logging-input (0 references)
pkts bytes target prot opt in out source destination
0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW BLOCK] "
Chain ufw-after-logging-output (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-after-output (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-before-forward (0 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 3
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 4
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 11
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 12
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 8
0 0 ufw-user-forward all -- * * 0.0.0.0/0 0.0.0.0/0
Chain ufw-before-input (0 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
0 0 ufw-logging-deny all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate INVALID
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate INVALID
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 3
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 4
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 11
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 12
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 icmptype 8
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp spt:67 dpt:68
0 0 ufw-not-local all -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT udp -- * * 0.0.0.0/0 224.0.0.251 udp dpt:5353
0 0 ACCEPT udp -- * * 0.0.0.0/0 239.255.255.250 udp dpt:1900
0 0 ufw-user-input all -- * * 0.0.0.0/0 0.0.0.0/0
Chain ufw-before-logging-forward (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-before-logging-input (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-before-logging-output (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-before-output (0 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * lo 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
0 0 ufw-user-output all -- * * 0.0.0.0/0 0.0.0.0/0
Chain ufw-logging-allow (0 references)
pkts bytes target prot opt in out source destination
0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW ALLOW] "
Chain ufw-logging-deny (2 references)
pkts bytes target prot opt in out source destination
0 0 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 ctstate INVALID limit: avg 3/min burst 10
0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10 LOG flags 0 level 4 prefix "[UFW BLOCK] "
Chain ufw-not-local (1 references)
pkts bytes target prot opt in out source destination
0 0 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type LOCAL
0 0 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type MULTICAST
0 0 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0 ADDRTYPE match dst-type BROADCAST
0 0 ufw-logging-deny all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 10
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
Chain ufw-reject-forward (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-reject-input (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-reject-output (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-skip-to-policy-forward (0 references)
pkts bytes target prot opt in out source destination
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
Chain ufw-skip-to-policy-input (7 references)
pkts bytes target prot opt in out source destination
0 0 DROP all -- * * 0.0.0.0/0 0.0.0.0/0
Chain ufw-skip-to-policy-output (0 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0
Chain ufw-track-forward (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-track-input (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-track-output (0 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 ctstate NEW
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 ctstate NEW
Chain ufw-user-forward (1 references)
pkts bytes target prot opt in out source destination
Chain ufw-user-input (1 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:22
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:22
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:443
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:443
Chain ufw-user-limit (0 references)
pkts bytes target prot opt in out source destination
0 0 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 limit: avg 3/min burst 5 LOG flags 0 level 4 prefix "[UFW LIMIT BLOCK] "
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable
Chain ufw-user-limit-accept (0 references)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0
Chain ufw-user-logging-forward (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-user-logging-input (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-user-logging-output (0 references)
pkts bytes target prot opt in out source destination
Chain ufw-user-output (1 references)
pkts bytes target prot opt in out source destination
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mch*_*hid 18
打开终端并键入以下命令:
首先进行重置,这将删除所有现有规则:
sudo ufw reset
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下一个,
sudo ufw app list
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这将列出可用的应用程序配置文件,例如 OpenSSH 等。要获取有关应用程序的信息,请在此示例中键入以下命令:
sudo ufw app info OpenSSH
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这是输出:
Profile: OpenSSH
Title: Secure shell server, an rshd replacement
Description: OpenSSH is a free implementation of the Secure Shell protocol.
Port:
22/tcp
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要允许 OpenSSH 访问,您可以使用以下规则:
sudo ufw allow 22/tcp
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与 Debian 不同,www 和 https 通常不作为应用程序配置文件包含在内,但是,我们知道它们在端口 80 和 443 上运行,因此请使用以下命令:
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
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如果您想添加 UDP,也可以这样做。
sudo ufw allow 80/udp
sudo ufw allow 443/udp
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禁用并启用 ufw 以应用更改:
sudo ufw disable
sudo ufw enable
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要显示您的规则:
sudo ufw status
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最后,ufw 不太友好的方面之一是拒绝规则通常胜过允许规则。例如,您不能将所有内容都设置为拒绝,然后将端口设置为允许。所有端口仍将被阻止。请参阅此处了解更多信息。
您可以添加这些规则以全局阻止除 22、53、80 和 443 之外的所有端口。我添加了端口 53 以允许 DNS 请求。如果您不需要进行 DNS 查询,只需相应地修改规则即可。
例如,要仅为传入设置这些阻止规则,您可以使用sudo ufw deny in 1:22/tcp。或者,设置为传出sudo ufw deny out 1:22/tcp等。
sudo ufw deny 1:21/tcp
sudo ufw deny 1:21/udp
sudo ufw deny 23:52/tcp
sudo ufw deny 23:52/udp
sudo ufw deny 54:79/tcp
sudo ufw deny 54:79/udp
sudo ufw deny 81:442/tcp
sudo ufw deny 81:442/udp
sudo ufw deny 444:65535/tcp
sudo ufw deny 444:65535/udp
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小智 9
仅供参考:以防其他人遇到此问题。
在详细的 iptables 输出中,我注意到 INPUT、OUTPUT 和 FORWARD 链中缺少 ufw 规则。当我在某个时候启用 ufw 后运行 iptables -F 以删除我的自定义 FW 规则时,我的系统最终会变成这样。如果 iptables 中已经存在一些自己的链,则 ufw 似乎不会重新添加顶级规则。
我最终卸载了 ufw,重新启动,运行 'iptables -F'(以删除以前仍处于活动状态的 iptables 规则),然后重新安装和配置 ufw。顶级 ufw 规则现在又回来了。卸载/重新安装可能不是必需的。只需通过禁用 ufw 并重新启动来从 iptables 中删除所有 ufw 规则就可以解决问题。
这是顶级链的样子(在 Debian 9.4 上)。
Chain INPUT (policy DROP)
target prot opt source destination
ufw-before-logging-input all -- 0.0.0.0/0 0.0.0.0/0
ufw-before-input all -- 0.0.0.0/0 0.0.0.0/0
ufw-after-input all -- 0.0.0.0/0 0.0.0.0/0
ufw-after-logging-input all -- 0.0.0.0/0 0.0.0.0/0
ufw-reject-input all -- 0.0.0.0/0 0.0.0.0/0
ufw-track-input all -- 0.0.0.0/0 0.0.0.0/0
Chain FORWARD (policy DROP)
target prot opt source destination
ufw-before-logging-forward all -- 0.0.0.0/0 0.0.0.0/0
ufw-before-forward all -- 0.0.0.0/0 0.0.0.0/0
ufw-after-forward all -- 0.0.0.0/0 0.0.0.0/0
ufw-after-logging-forward all -- 0.0.0.0/0 0.0.0.0/0
ufw-reject-forward all -- 0.0.0.0/0 0.0.0.0/0
ufw-track-forward all -- 0.0.0.0/0 0.0.0.0/0
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
ufw-before-logging-output all -- 0.0.0.0/0 0.0.0.0/0
ufw-before-output all -- 0.0.0.0/0 0.0.0.0/0
ufw-after-output all -- 0.0.0.0/0 0.0.0.0/0
ufw-after-logging-output all -- 0.0.0.0/0 0.0.0.0/0
ufw-reject-output all -- 0.0.0.0/0 0.0.0.0/0
ufw-track-output all -- 0.0.0.0/0 0.0.0.0/0
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