Net::Cisco::AccessList::Extended - Generate Cisco extended access-lists

This document refers to version 1.01 of Net::Cisco::AccessList::Extended.

 use Net::Cisco::AccessList::Extended;
 my $l = Net::Cisco::AccessList::Extended->new('INCOMING_LIST');

 $l->push({
     access  => 'permit',
     proto   => 'ip',
     src_og  => 'friendly_net',
     dst_og  => 'local_net',
 });

 print $l->dump, "\n";
 # prints the access-list commands to STDOUT, something like:

 access-list INCOMING_LIST extended permit ip object-group friendly_net object-group local_net

Use this module to manage the presentation of Cisco Extended Access Lists. List entries are pushed into the object in a simple parmaterized fashion, and you can then dump the list in a format that is parsable by Cisco devices.

Support is included for list entries that reference Object Groups (as used by more recent PIX OS and FWSM software versions).

This module's error checking is only concerned with syntactic correctness. It makes no judgement of the semantic correctness of your list entries.

For instance, newer FWSM systems use netmasks specified in terms of host address network masks (e.g. 255.255.255.0), whereas older systems use wildcard bits (e.g. 0.0.0.255). Net::Cisco::AccessList::Extended will not check that you use the correct type of mask, or even that your mask isn't something completely inappropriate (e.g. cabbages).

Each access list that you manage must be created through this method, which takes one parameter, the name of the access list.

On success this method returns a newly instatiated Net::Cisco::AccessList::Extended object. Lucky you.

Use this method to add an access list entry (sometimes called an Access Control Entry by Cisco documentation) to the end of an access list. In case it is not obvious, access lists are ordered, so pushing an entry means it is added to the end of the list.

Parameters are all passed within a single hash reference argument. Which keys of that hash you populate will depend on the Access Control Entry (hereafter, ACE) that you are appending to the access list. Logic within the module should check that you are syntactically correct, but for brevity of this documentation you are referred to the many Cisco manuals containing ACE syntax usage guidelines.

Possible keys and values are as follows:

access

This parameter is required and dictates whether the ACE will be a permit or deny rule, with the following values being interpreted as meaning permit:

 Permit | permit | 1

Any other value in this slot is taken to be a request for a deny statement.

proto or proto_og

Network protocol. As mentioned above, it is your responsibility to enter something that the Cisco device will parse (e.g. a recognised protocol name or IANA assigned number, or protocol object group). This parameter is required.

src_ip, src_mask or src_og

Source network. Various combinations of these three keys are permitted. Omitting them all results in the keyword any being used. Only providing the src_ip is allowed, as well as providing both the src_ip and src_mask. Alterntively you may specify an object group in the src_og slot.

src_svc_op, src_svc, src_svc_hi or src_svc_og

Source port(s). Again, various combinations of these keys are permitted. A service (aka port) object group is used by only filling the src_svc_og slot. Otherwise, src_svc_op is required and is the service operator (e.g. gt, eq, etc). src_svc is the service name or IANA assigned port number, and if the operator is range then the upper port boundary must be provided in the src_svc_hi slot.

dst_ip, dst_mask or dst_og

These keys function identically to their src_ counterparts, but of course control the production of destination network address fields.

dst_svc_op, dst_svc, dst_svc_hi or dst_svc_og

These keys function identically to their src_ counterparts, but of course control the production of destination service fields.

icmp or icmp_og

Any value in this slot will be appended to the ACE, so that you can limit the match to a particular ICMP message type if the rule's protocol is icmp. Use icmp_og if your value is the name of an icmp object group.

On success this method returns its own object. On failure this module will die.

This method generates and returns the access list as it would look in a Cisco configuration file.

The returned value is a scalar, with embedded newline characters and no terminating newline, so you will need to append that as required. Note that when submitting this to, for example, a Net::Appliance::Session session via cmd(), a newline will be automatically appended by that method.

Fully compatible Cisco commands are produced on the fly from the data stored in the Net::Cisco::AccessList::Extended object, so you can dump and push repeatedly to your heart's content.

missing parameter for list name

You have not provided the required parameter to new(), see "METHODS".

Various other missing... or cannot... messages

These are generated by the internal syntax checking routine, which will alert you to conflicting parameters passed to the push object method.

Other than the contents of the standard Perl distribution, you will need the following:

• Class::Accessor::Fast (bundled with Class::Accessor)
• List::MoreUtils

Net::Cisco::ObjectGroup, Net::Appliance::Session

Oliver Gorwits <oliver.gorwits@oucs.ox.ac.uk>

Copyright (c) The University of Oxford 2008.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.