unbntn防火墙ufw的说明页

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很与众不同。与其他Linux一般使用IPTABLES不同，特记录下。

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UFW:(8) August2009 UFW:(8)

NAME
ufw - program for managing a netfilter firewall

DESCRIPTION
This program is for managing a Linux firewall and aims toprovide an
easy to use interface for the user.

USAGE
ufw [--dry-run] enable|disable|reload

ufw [--dry-run] default allow|deny|reject [incoming|outgoing]

ufw [--dry-run] logging on|off|LEVEL

ufw [--dry-run] reset

ufw [--dry-run] status [verbose|numbered]

ufw [--dry-run] show REPORT

ufw [--dry-run] delete NUM

ufw [--dry-run] app list|info|default|update

OPTIONS
--version
show program's version number and exit

-h, --help
show help message and exit

--dry-run
don't modify anything, just show the changes

enable reloads firewall and enables firewall on boot.

disable
unloads firewall and disables firewall on boot

reload reloads firewall

      default allow|deny|reject DIRECTION
             change the default policy for trafficgoing DIRECTION, where
             DIRECTION is one of incoming or outgoing. Note that existing
             rules will have to be migrated manually when changingthe
             default policy. See RULE SYNTAX for more on deny and reject.

      logging on|off|LEVEL
             toggle logging. Logged packets use the LOG_KERN syslogfacility.
             Systems  configured  for rsyslog support may also log to
             /var/log/ufw.log. Specifying a LEVEL turnslogging on for the
             specified LEVEL. The default log level is 'low'. See LOGGING
             for details.

      reset Disables and resets firewall toinstallation defaults. Can also
             give the --force option toperform the reset without confirma‐
             tion.

      status show status of firewall and ufw managed rules.Use status ver‐
             bose for extra information. In the status output,'Anywhere' is
             synonymous with 'any' and '0.0.0.0/0'.

show REPORT
display information about the running firewall. See REPORTS

allow ARGS
add allow rule. See RULE SYNTAX

deny ARGS
add deny rule. See RULE SYNTAX

reject ARGS
add reject rule. See RULE SYNTAX

      limit ARGS
             add limit rule. Currently onlyIPv4 is supported.  See RULE
             SYNTAX

delete RULE|NUM
deletes the corresponding RULE

insert NUM RULE
insert the corresponding RULE as rule number NUM

RULE SYNTAX
      Users can specify rules using either a simplesyntax or a full syntax.
      The simple syntax only specifies the port andoptionally the protocol
      to be allowed or denied on the host. For example:

ufw allow 53

This rule will allow tcp andudp port 53 to any address on this host.
To specify a protocol, append '/protocol' to the port. Forexample:

ufw allow 25/tcp

      This will allow tcp port 25 to any address on this host. ufwwill also
      check /etc/services for theport and protocol if specifying a service
      by name. Eg:

ufw allow smtp

      ufw supports both ingress and egress filtering and users mayoptionally
      specify a direction of either in or out for either incoming oroutgoing
      traffic. If no direction is supplied, the rule applies to incoming
      traffic. Eg:

ufw allow in http
ufw reject out smtp

      Users can also use a fuller syntax, specifyingthe source and destina‐
      tion addresses and ports. This syntax is based on OpenBSD'sPF syntax.
      For example:

ufw deny proto tcp to any port 80

This will deny all traffic totcp port 80 on this host. Another exam‐
ple:

ufw deny proto tcp from 10.0.0.0/8 to 192.168.0.1 port 25

This will deny all traffic from the RFC1918 Class A network to tcpport
25 with the address 192.168.0.1.

ufw deny proto tcp from 2001:db8::/32 to any port 25

      This will deny all traffic fromthe IPv6 2001:db8::/32 to tcp port 25
      on this host. Note that IPv6 must be enabled in /etc/default/ufw for
      IPv6 firewalling to work.

ufw allow proto tcp from any to any port 80,443,8080:8090

      The above will allow all traffic to tcpports 80, 443 and 8080-8090
      inclusive. Note that when specifying multipleports, the ports list
      must be numeric, cannot contain spaces and must be modified as awhole.
      Eg, in the above example you cannot later try to delete justthe '443'
      port. You cannot specify morethan 15 ports (ranges count as 2 ports,
      so the port count in the above example is 4).

      ufw supports connection rate limiting, which isuseful for protecting
      against brute-force loginattacks. ufw will deny connections if an IP
      address has attempted to initiate 6 or more connections in thelast 30
      seconds.   See http://www.debian-administration.org/articles/187 for
      details. Typical usage is:

ufw limit ssh/tcp

      Sometimes it is desirable to let the sender know when trafficis being
      denied, rather than simply ignoring it. In these cases, use reject
      instead of deny. For example:

ufw reject auth

      By default, ufw will apply rules to all available interfaces.To limit
      this, specify DIRECTION onINTERFACE, where DIRECTION is one of in or
      out (interface aliases are not supported). Forexample, to allow all
      new incoming http connections on eth0, use:

ufw allow in on eth0 to any port 80 proto tcp

To delete a rule, simply prefix theoriginal rule with delete. For
example, if the original rule was:

ufw deny 80/tcp

Use this to delete it:

ufw delete deny 80/tcp

You may also specify the rule by NUM, as seen in the status numbered
output. For example, if you want to delete rule number '3',use:

ufw delete 3

      If you have IPv6 enabled andare deleting a generic rule that applies
      to both IPv4 and IPv6 (eg 'ufw allow 22/tcp'), deleting byrule number
      will delete only the specifiedrule. To delete both with one command,
      prefix the original rule with delete.

      To insert a rule, specify the new rule as normal, butprefix the rule
      with the rule number to insert. For example, if you have four rules,
      and you want to insert a new rule as rule number three, use:

ufw insert 3 deny to any port 22 from 10.0.0.135 proto tcp

To see a list of numbered rules, use:

ufw status numbered

      ufw supports per rule logging. By default, no logging is performedwhen
      a packet matches a rule. Specifying log will log all newconnections
      matching the rule, and log-all will log all packets matchingthe rule.
      For example, to allow and log all new ssh connections, use:

ufw allow log 22/tcp

See LOGGING for more information on logging.

EXAMPLES
Deny all access to port 53:

ufw deny 53

Allow all access to tcp port 80:

ufw allow 80/tcp

Allow all access from RFC1918 networks to this host:

        ufw allow from 10.0.0.0/8
        ufw allow from 172.16.0.0/12
        ufw allow from 192.168.0.0/16

Deny access to udp port 514 from host 1.2.3.4:

ufw deny proto udp from 1.2.3.4 to any port 514

Allow access to udp 1.2.3.4 port 5469 from 1.2.3.5 port 5469:

ufw allow proto udp from 1.2.3.5 port 5469 to 1.2.3.4 port 5469

REMOTE MANAGEMENT
      When running ufw enable or starting ufw via its initscript,ufw will
      flush its chains. This is required so ufw can maintain a consistent
      state, but it may drop existing connections (egssh). ufw does support
      adding rules before enabling the firewall, so administrators cando:

ufw allow proto tcp from any to any port 22

      before running 'ufw enable'. The rules will still beflushed, but the
      ssh port will be open after enabling the firewall. Please notethat
      once ufw is 'enabled', ufw will not flush the chains when adding or
      removing rules (but will when modifying a rule orchanging the default
      policy). By default, ufw will prompt when enablingthe firewall while
      running under ssh. This can be disabled by using 'ufw --forceenable'.

APPLICATION INTEGRATION
      ufw supports application integration byreading profiles located in
      /etc/ufw/applications.d. To list the names of application profiles
      known to ufw, use:

ufw app list

Users can specify one of the applications nameswhen adding rules. For
example, when using the simple syntax, users can use:

ufw allow <name>

Or for the extended syntax:

ufw allow from 192.168.0.0/16 to any app<name>

You should not specify the protocol with eithersyntax, and with the
extended syntax, use app in place of the port clause.

Details on the firewall profile for agiven application can be seen
with:

ufw app info <name>

      where '<name>' is one of theapplications seen with the app list com‐
      mand.   User's may also specify all to see the profiles for allknown
      applications.

After creating or editing an application profile, user's canrun:

ufw app update <name>

      This command will automatically update the firewallwith updated pro‐
      file information. If specify 'all' for name, then all the profileswill
      be updated. To update a profile and add anew rule to the firewall
      automatically, user's can run:

ufw app update --add-new <name>

The behavior of the update --add-new command can be configuredusing:

ufw app default <policy>

      The default application policy is skip,which means that the update
      --add-new command will do nothing. Users may also specifya policy of
      allow or deny so the update --add-new command mayautomatically update
      the firewall. WARNING: it may be a security torisk to use a default
      allow policy for applications profiles. Carefully consider thesecurity
      ramifications before using a default allow policy.

LOGGING
      ufw supports multiple logging levels. ufwdefaults to a loglevel of
      'low' when a loglevel is not specified. Users may specify a loglevel
      with:

ufw logging LEVEL

LEVEL may be 'off', 'low', 'medium', 'high' andfull. Log levels are
defined as:

off disablesufw managed logging

low logs all blocked packets notmatching the default policy (with
rate limiting), as well as packets matching logged rules

      medium log level low, plus all allowed packets not matching thedefault
             policy, all INVALID packets, and all newconnections. All log‐
             ging is done with rate limiting.

high log level medium (withoutrate limiting), plus all packets with
rate limiting

full log level high withoutrate limiting

      Loglevels above medium generate a lot of logging output, and may
      quickly fill up your disk. Loglevel medium may generate alot of log‐
      ging output on a busy system.

Specifying 'on' simply enables logging at log level 'low' iflogging is
currently not enabled.

REPORTS
      The following reports are supported. Each is based onthe live system
      and with the exception of the listening report, is in raw iptablesfor‐
      mat:

        raw
        builtins
        before-rules
        user-rules
        after-rules
        logging-rules
        listening

The raw report shows the complete firewall, while the others show a
subset of what is in the raw report.

      The listening report willdisplay the ports on the live system in the
      listening state for tcp and the open state for udp, along with the
      address of the interface andthe executable listening on the port. An
      '*' is used in place of the address of the interface when the exe‐
      cutable is bound to all interfaces on that port.Following this infor‐
      mation is a list of rules which may affectconnections on this port.
      The rules are listed in the order they are evaluated by the kernel,and
      the first match wins. Please note that the default policy is notlisted
      and tcp6 and udp6 are shown only if IPV6 is enabled.

NOTES
      On installation, ufw is disabled with a default incoming policy ofdeny
      and a default outgoing policy of allow, with stateful trackingfor NEW
      connections. Having a default policy of allow without statefultracking
      can be achieved by using ACCEPT_NO_TRACK instead of ACCEPT   in
      /etc/defaults/ufw.

      Rule ordering is important and the firstmatch wins. Therefore when
      adding rules, add the more specific rules first with more generalrules
      later.

      ufw is not intended to provide complete firewallfunctionality via its
      command interface, but instead provides an easy wayto add or remove
      simple rules. It is currently mainly used for host-basedfirewalls.

      The status command shows basic information about the state of thefire‐
      wall, as well as rules managed via the ufw command.It does not show
      rules from the rules files in /etc/ufw. To see the completestate of
      the firewall, users can ufw show raw. Thisdisplays the filter, nat,
      mangle and raw tables using:

iptables -n -L -v -x -t <table>
ip6tables -n -L -v -x -t <table>

See the iptables and ip6tables documentation for more details.

If the default policy is set to REJECT, ufw mayinterfere with rules
added outside of the ufw framework. See README for details.

      IPv6 is blocked by default and only IPv6 traffic on the loopbackinter‐
      face is allowed. To change this behavior, set IPV6 to 'yes' in
      /etc/defaults/ufw and reload ufw. Once IPv6 is enabled, you mayspecify
      rules in the same way as for IPv4 rules, and they will bedisplayed
      with ufw status. Rules that match both IPv4 and IPv6 addressesapply to
      both IP versions. For example, when IPv6 is enabled, the followingrule
      will allow access to port 22 for both IPv4 and IPv6 traffic:

ufw allow 22

      IPv6 over IPv4 tunnels and 6to4 are supported by using the'ipv6' pro‐
      tocol ('41'). This protocol can only be used withthe full syntax. For
      example:

ufw allow to 10.0.0.1 proto ipv6
ufw allow to 10.0.0.1 from 10.4.0.0/16 proto ipv6

IPSec is supported by using the 'esp' ('50') and 'ah' ('51')protocols.
These protocols can only be used with the full syntax. Forexample:

        ufw allow to 10.0.0.1 proto esp
        ufw allow to 10.0.0.1 from 10.4.0.0/16 proto esp
        ufw allow to 10.0.0.1 proto ah
        ufw allow to 10.0.0.1 from 10.4.0.0/16 proto ah

      In addition to the command-lineinterface, ufw also provides a frame‐
      work which allows administrators to take fulladvantage of netfilter.
      See the ufw-framework manual page for more information.

SEE ALSO
ufw-framework, iptables(8), ip6tables(8), iptables-restore(8),
ip6tables-restore(8), sysctl(8), sysctl.conf(5)

ufw and this manual page was originally written by Jamie Strandboge
<jamie@canonical.com>

August2009 UFW:(8)