Make Decisions

MTA Configuration Commands for Offramp Fax

Permanent-error directs the T.37 offramp fax gateway to classify all fax delivery errors as permanent so that they are forwarded in SMTP DSN messages with descriptive error codes to an MTA. The descriptive error codes allow the MTA to control fax operations directly because the MTA can examine the error codes and make decisions about how to proceed with each fax (whether to retry or cancel, for example).

Using the PISA for Enhanced Traffic Detection

PISA is a hardware subsystem of the Supervisor 32. The PISA has the capability to detect classify protocols, and consequently make decisions on the FWSM to forward or deny traffic can be applied by application type. The PISA uses Network-based Application Recognition (NBAR) and Flexible Packet Matching (FPM) to classify traffic. Both NBAR and FPM use a process of deep packet inspection to determine traffic types. This looks beyond Layer 4 ports and into the data portion of the packet therefore, applications using nonstandard ports can be detected. The minimum supervisor code requirement is 12.2(18)ZYA.

Do I Know This Already Klo

PAT is based on source port the destination port is not altered but is taken into consideration when making decisions. For example, a Telnet connection is based on the local port number (a random number generated by the device between 0 and 65,535) and the destination port number 23.

Test optimize and document the design

Network security design development This step develops a strategy, plan, and design for integrating a new security solution into the core network infrastructure. The design team reviews the security goals of the organization and defines an in-depth analysis of the technical, procedural, and resource requirements for a customized security deployment that meets these goals. You will also make decisions on the hardware, software, and sample configurations for the intended solution. Here are the key steps

Multicast Listener Discovery

In Cisco switches, MLD snooping provides the same functionality as IGMP snooping for IPv4. That is, it provides information to the switch about which connected hosts are members of a particular multicast group so that the switch can make decisions about whether, and on which interfaces, to allow traffic for that group to flow through the switch.

Strive for Operational Simplicity

Network designers make decisions regarding operational complexity every day. Most don't call it that, though they tend to think along the lines of the difficulty and burden that specific technology places on administrators or users. This section gets to a key aspect of your network security system achieving operational simplicity can mean the difference between a security system that works for you and a security system that you work for.

Configuring a LACP Ether Channel

First, the switch should have its LACP system priority defined (1 to 65,535 default 32,768). If desired, one switch should be assigned a lower system priority than the other so that it can make decisions about the EtherChannel's makeup. Otherwise, both switches will have the same system priority (32,768), and the one with the lower MAC address will become the decision maker.

Configuring Content Filters

By default, if none of the filtering servers is available, the HTTP requests are dropped. This assumes that the filtering policies must be strictly enforced, requiring filtering servers to make decisions at all times. If this is too restrictive for your environment, you can add the allow keyword so that HTTP requests are allowed by the firewall if no filtering servers respond.

The Difficulties of Secure Networking

Second, network identity is hard to track. As a user of the network, you, or your host, can be identified by your Media Access Control (MAC) address, IP address, username, or a certificate. Because security systems make decisions at different layers of the network, it can be difficult to ensure consistent policy implementation across these boundaries.

IP Addressing

For the purpose of this discussion, assume that you have a large Ethernet segment that is so full of users that the collisions occurring on it are negatively impacting the users' and the segments' performance. The easy fix is to use a bridge that enables you to split the network but retain connectivity. The problem here is that bridges use MAC addresses to make decisions on where to forward packets. However, if the bridge does not know where to send a packet, it resorts to broadcasting it to everyone. Your slow, busy Ethernet segment will have been split into two segments your network performance should increase as a result. The problem is that as you begin to connect more segments, you end up with broadcasts flowing all across the network to the point that the intranet might come to a standstill. Large amounts of broadcasts, such as those described here, are typically called broadcast storms, which are a bad thing.

BGP Communities

Additionally, BGP includes several reserved values for the COMMUNITY PA that allow route filtering to occur, but with less effort than is required with community lists and route maps. These special COMMUNITY values, once set, affect the logic used by routers when making decisions about to which BGP peers they will advertise the route. The values are listed in Table 13-16.

Case Studies

Another lesson learned according to Garcia is to establish a governance model for portal content early in the process. In the beginning, it was problematic, he says. Somebody needs to be empowered to make decisions about content and strategy. The community model is working well for us, with local people creating and managing local content. If I were to do this again, I would involve the business units and all geographies from the beginning. We designed the governance model when we were in the middle.

Network Firewalls

Many network firewalls provide enterprise users the maximum flexibility and protection in a firewall system. These firewalls have over the past few years incorporated many new features such as in-line intrusion detection and prevention as well as virtual private network (VPN) termination capabilities both for LAN-to-LAN VPNs as well as remote-access-user VPNs. Another feature that has been introduced into network firewalls is a deep packet-inspection capability. The firewall can identify traffic requirements not just by looking at Layer 3 and Layer 4 information but by delving all the way into the application data so that the firewall can make decisions as to how to best handle the traffic flow. This evolution in firewall design and capabilities has led to the development of a new firewall product, the integrated firewall, which is covered in more detail in the next section.