shorewall_code/STABLE/documentation/Accounting.html
2003-10-08 14:55:42 +00:00

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<title>Shorewall Accounting</title>
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<h1 align="center"><font color="#ffffff">Shorewall and Traffic
Accounting</font></h1>
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Shorewall Traffic Accounting support was added in Shorewall release
1.4.7.<br>
<br>
Shorewall accounting rules are described in the file
/etc/shorewall/accounting. By default, the accounting rules are placed
in a chain called "accounting" and can
thus be displayed using "shorewall show accounting". All traffic
passing into, out of or through the firewall traverses the accounting
chain including traffic that will later be rejected by <a
href="Documentation.htm#Interfaces">interface options</a> such as
"tcpflags" and "maclist". If your kernel doesn't support the connection
tracking match extension (Kernel 2.4.21) then some traffic rejected
under 'norfc1918' will not traverse the accounting chain.<br>
<br>
The columns in the accounting file are as follows:<br>
<ul>
<li><span style="font-weight: bold;">ACTION</span> - What to do when
a match is found. Possible values are:</li>
<ul>
<li>COUNT- Simply count the match and&nbsp; continue trying to
match the packet with the following accounting rules</li>
<li>DONE- Count the match and don't attempt to match any following
accounting rules.</li>
<li>&lt;<span style="font-style: italic;">chain</span>&gt; - The
name of a chain to jump to. Shorewall will create the chain
automatically. If the
name of the chain is followed by ":COUNT" then a COUNT rule matching
this rule will automatically be added to &lt;<span
style="font-style: italic;">chain</span>&gt;<br>
</li>
</ul>
<li><span style="font-weight: bold;">CHAIN </span>- The name of the
chain where the accounting rule is to be added. If empty or "-" then
the "accounting" chain is assumed.<br>
</li>
<li><span style="font-weight: bold;">SOURCE</span> - Packet Source.
The name of an interface, an address
(host or net) or an interface name followed by ":" and a host or net
address.</li>
<li><span style="font-weight: bold;">DESTINATION</span> - Packet
Destination Format the same as the SOURCE
column.</li>
<li><span style="font-weight: bold;">PROTOCOL</span> - A protocol
name (from /etc/protocols) or a protocol
number.</li>
<li><span style="font-weight: bold;">DEST PORT</span> - Destination
Port number. Service name from
/etc/services or port number. May only be specified if the protocol is
TCP or UDP (6 or 17).</li>
<li><span style="font-weight: bold;">SOURCE PORT</span>- Source Port
number. Service name from /etc/services
or port number. May only be specified if the protocol is TCP or UDP (6
or 17).<br>
</li>
</ul>
In all columns except ACTION and CHAIN, the values "-","any" and
"all" are treated as wild-cards.<br>
&nbsp;<br>
The accounting rules are evaluated in the Netfilter 'filter' table.
This is the same environment where the 'rules' file rules are evaluated
and in this environment, DNAT has already occurred in inbound packets
and SNAT has not yet occurred on outbound ones.<br>
&nbsp;<br>
Accounting rules are not stateful -- each rule only handles traffic in
one direction. For example, if eth0 is your internet interface and you
have a web
server in your DMZ connected to eth1 then to count HTTP traffic in
both directions requires two rules:&nbsp;<br>
<pre> #ACTION CHAIN SOURCE DESTINATION PROTOCOL DEST SOURCE<br> # PORT PORT<br> DONE - eth0 eth1 tcp 80<br> DONE - eth1 eth0 tcp - 80</pre>
Associating a counter with a chain allows for nice reporting. For
example:<br>
<pre> #ACTION CHAIN SOURCE DESTINATION PROTOCOL DEST SOURCE<br> # PORT PORT<br> web:COUNT - eth0 eth1 tcp 80<br> web:COUNT - eth1 eth0 tcp - 80<br> web:COUNT - eth0 eth1 tcp 443<br> web:COUNT - eth1 eth0 tcp - 443<br> DONE web<br></pre>
Now "shorewall show web" will give you a breakdown of your web traffic:<br>
<div style="margin-left: 40px;">
<pre>[root@gateway shorewall]# shorewall show web<br>Shorewall-1.4.6-20030821 Chain web at gateway.shorewall.net - Wed Aug 20 09:48:56 PDT 2003<br> <br>Counters reset Wed Aug 20 09:48:00 PDT 2003<br> <br>Chain web (4 references)<br> pkts bytes target prot opt in out source destination<br> 11 1335 tcp -- eth0 eth1 0.0.0.0/0 0.0.0.0/0 tcp dpt:80<br> 18 1962 tcp -- eth1 eth0 0.0.0.0/0 0.0.0.0/0 tcp spt:80<br> 0 0 tcp -- eth0 eth1 0.0.0.0/0 0.0.0.0/0 tcp dpt:443<br> 0 0 tcp -- eth1 eth0 0.0.0.0/0 0.0.0.0/0 tcp spt:443<br> 29 3297 RETURN all -- * * 0.0.0.0/0 0.0.0.0/0<br>[root@gateway shorewall]#</pre>
</div>
Here's a slightly different example:<br>
<pre> #ACTION CHAIN SOURCE DESTINATION PROTOCOL DEST SOURCE<br> # PORT PORT<br> web - eth0 eth1 tcp 80<br> web - eth1 eth0 tcp - 80<br> web - eth0 eth1 tcp 443<br> web - eth1 eth0 tcp - 443<br><br> COUNT web eth0 eth1<br> COUNT web eth1 eth0<br></pre>
Now "shorewall show web" simply gives you a breakdown by input and
output:<br>
<br>
<pre style="margin-left: 40px;">[root@gateway shorewall]# shorewall show accounting web <br>Shorewall-1.4.6-20030821 Chains accounting web at gateway.shorewall.net - Wed Aug 20 10:27:21 PDT 2003<br> <br>Counters reset Wed Aug 20 10:24:33 PDT 2003<br> <br>Chain accounting (3 references)<br> pkts bytes target prot opt in out source destination<br> 8767 727K web tcp -- eth0 eth1 0.0.0.0/0 0.0.0.0/0 tcp dpt:80<br> 0 0 web tcp -- eth0 eth1 0.0.0.0/0 0.0.0.0/0 tcp dpt:443<br>11506 13M web tcp -- eth1 eth0 0.0.0.0/0 0.0.0.0/0 tcp spt:80<br> 0 0 web tcp -- eth1 eth0 0.0.0.0/0 0.0.0.0/0 tcp spt:443<br>Chain web (4 references)<br> pkts bytes target prot opt in out source destination<br> 8767 727K all -- eth0 eth1 0.0.0.0/0 0.0.0.0/0<br>11506 13M all -- eth1 eth0 0.0.0.0/0 0.0.0.0/0<br>[root@gateway shorewall]#<br><br></pre>
<p align="left"><font size="2">Last updated 8/20/2003 - <a
href="support.htm">Tom Eastep</a></font></p>
<p><font face="Trebuchet MS"><a href="copyright.htm"><font size="2">Copyright</font>
<EFBFBD> <font size="2">2003 Thomas M. Eastep.</font></a></font></p>
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