IPChains 0.5

IPChains is a Perl module to create and manipulate ipchains via Perl.

SYNOPSIS

use IPChains;
$fw = IPChains->new(-option => value, ... ); $fw->append(chain);

This module acts as an interface to the ipchains(8) userspace utility by Paul "Rusty" Russell (http://www.rustcorp.com/linux/ipchains/). It attempts to include all the functionality of the original code with a simplified user interface via Perl. In addition, plans for log parsing facilities, an integrated interface to ipmasqadm, and possibly traffic shaping are slated for up and coming versions.
The new() and attribute() methods support the following options:

Source

Specifies origination address of packet. Appending hostmask to this address using a / is OK, as well as specifying it separately (see SourceMask).

SourceMask

Hostmask for origination address. Can either be in 24 or 255.255.255.0 style.

SourcePort

Specific port or port range (use xxx:xxx to denote range), requires specific protocol specification.

Dest

Specifies destination address of packet. Appending hostmask to this address using a / is OK, as well as specifying it separately (see DestMask)

DestMask

Destination address, (see SourceMask).

DestPort

Destination Port, (see SourcePort).

Prot

Protocol. Can be tcp, udp, icmp, or all. Required for specifying specific port(s).

ICMP

ICMP Name/Code (in place of port when ICMP is specified as protocol).

Here is a small table of some of the most common ICMP packets:

Number Name Required by

0 echo-reply ping
3 destination-unreachable Any TCP/UDP traffic.
5 redirect routing if not running
routing daemon
8 echo-request ping
11 time-exceeded traceroute

Rule

Target. Can be ACCEPT, DENY, REJECT, MASQ, REDIRECT, RETURN, or a user-defined chain. Note: This is case sensitive.

Interface

Specify a specify interface as part of the criteria (ie, eth0, ppp0, etc.).

Fragment

Rule only refers to second and further fragments of fragmented packets (1 or 0).

Bidir

Makes criteria effective in both directions (1 or 0).

Verbose

Set verbose option for setting rules or list() (1 or 0).

Numeric

Show output from list() in numeric format. No DNS lookups, etc.. (1 or 0).

Log

Enable kernel logging (via syslog, kern.info) of matched packets (1 or 0).

Output

Copy matching packets to the userspace device (advanced).

Mark

Mark matching packets with specified number (advanced).

TOS

Used for modifying the TOS field in the IP header. Takes 2 args, AND and XOR masks, (ie, (TOS => ["0x01", "0x10"])). This feature is highly untested.
The first mask is ANDed with the packets current TOS, and the second mask is XORed with it. Use the following table for reference:

TOS Name Value Typical Uses

Minimum Delay 0x01 0x10 ftp, telnet
Maximum Throughput 0x01 0x08 ftp-data
Maximum Reliability 0x01 0x04 snmp
Minimum Cost 0x01 0x02 nntp

Exact

Display exact numbers in byte counters instead of numbers rounded in Ks, Ms, or Gs (1 or 0).

SYN

Only match TCP packets with the SYN bit set and the ACK and FIN bits cleared (1 or 0).