IPChains is a Perl module to create and manipulate ipchains via Perl.
$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:
Specifies origination address of packet. Appending hostmask to this address using a / is OK, as well as specifying it separately (see SourceMask).
Hostmask for origination address. Can either be in 24 or 255.255.255.0 style.
Specific port or port range (use xxx:xxx to denote range), requires specific protocol specification.
Specifies destination address of packet. Appending hostmask to this address using a / is OK, as well as specifying it separately (see DestMask)
Destination address, (see SourceMask).
Destination Port, (see SourcePort).
Protocol. Can be tcp, udp, icmp, or all. Required for specifying specific port(s).
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
8 echo-request ping
11 time-exceeded traceroute
Target. Can be ACCEPT, DENY, REJECT, MASQ, REDIRECT, RETURN, or a user-defined chain. Note: This is case sensitive.
Specify a specify interface as part of the criteria (ie, eth0, ppp0, etc.).
Rule only refers to second and further fragments of fragmented packets (1 or 0).
Makes criteria effective in both directions (1 or 0).
Set verbose option for setting rules or list() (1 or 0).
Show output from list() in numeric format. No DNS lookups, etc.. (1 or 0).
Enable kernel logging (via syslog, kern.info) of matched packets (1 or 0).
Copy matching packets to the userspace device (advanced).
Mark matching packets with specified number (advanced).
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 packet's 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
Display exact numbers in byte counters instead of numbers rounded in K's, M's, or G's (1 or 0).
Only match TCP packets with the SYN bit set and the ACK and FIN bits cleared (1 or 0).