Adding Network Objects for Mapped Addresses on CISCO ASA

Here are some general rules for dynamic NAT, you must use an object or group for the mapped addresses. Other NAT types have the option of using inline addresses, or you can create an object or group.
For more information about configuring a network object or group see below.

Guidelines

A network object group can contain objects and/or inline addresses of either IPv4 or IPv6 addresses. The group cannot contain both IPv4 and IPv6 addresses; it must contain one type only.

Clearing, resetting or erasing configuration on Cisco ASA

There are multiple different ways to do that but I prefer this two ways to clear my configuration from ASA.

First [ciscoasa# write erase] and second [ciscoasa(config)# configure factory-default]

There is option for configure factory-default command:

configure mode commands/options:

  Hostname or A.B.C.D  Specify optional management interface IP address

Which one to use, well, both does their job quite good. Clear configuration file to the basic configuration of ASA.

OSPF Virtual Link - CISCO -

The Backbone and Area 0

OSPF has special restrictions when multiple areas are involved. If more than one area is configured, one of these areas has to be area 0. This is called the backbone.

The backbone has to be at the center of all other areas, every other areas have to be physically connected to the area 0 (backbone area). The reasoning for this is that OSPF expects all areas to inject routing information into the backbone and in turn the backbone will spread out that information into other areas. When designing networks it is good practice to start with area 0 and then expand into other areas later on. 

If it is not possible to connect area to the backbone area 0 there is solution for that, we have tool that can be used, and that would be virtual link.

Virtual links are used for two purposes: 

• Linking an area that does not have a physical connection to the backbone.              

         See Example 1.

• Patching the backbone in case discontinuity of area 0 occurs. 

         See Example 2.