Tag Archives: juniper

How Juniper Standard Firewall Filters Evaluate Packets

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This post is critical for those students studying for their Enterprise Routing and Switching Certifications.

Firewall Filter Packet Evaluation Overview

The following sequence describes how the device evaluates a packet entering or exiting an interface if the input or output traffic at a device interface is associated with a firewall filter.

Packet evaluation proceeds as follows:

  1. The device evaluates the packet against the terms in the firewall filter sequentially, beginning with the first term in the filter.
  2. If the packet matches all the conditions specified in a term, the device performs all the actions specified in that term.
  3. If the packet does not match all the conditions specified in a term, the device proceeds to the next term in the filter (if a subsequent term exists) and evaluates the packet against that term.
  4. If the packet does not match any term in the firewall filter, the device implicitly discards the packet.

Unlike service filters and simple filters, firewall filters support the next term action, which is neither a terminating action nor a nonterminating action but a flow control action.

If the matched term includes the next term action, the device continues evaluation of the packet at the next term within the firewall filter.

If the matched term does not include the next term action, evaluation of the packet against the given firewall filter ends at this term. The device does not evaluate the packet against any subsequent terms in this filter.

A maximum of 1024 next term actions are supported per firewall filter configuration. If you configure a firewall filter that exceeds this limit, your candidate configuration results in a commit error.

The device stops evaluating a packet against a given firewall filter when either the packet matches a term without the next term action or the packet fails to match the last term in the firewall filter.

Juniper iBGP Peering Example

This Sneak Peek Nugget is from my BGP – Peering module at CBT Nuggets. This is one module of three on BGP that are currently complete and live on CBT Nuggets. These modules consist of many videos that provide detailed coverage on BGP with both Cisco and Juniper examples.

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Juniper Expands the “Test at Home” Option for Certification Exams!

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I have never done an exam this way with Juniper – but I plan to next week. I will do a full report here on the blog regarding the experience. You can test in the convenience of your home or office with the proctor monitoring you via Webcam!

The Juniper Networks Certification Program team has expanded the online proctoring (OP) option from our Associate-level exams only to now include our Specialist and Professional-level certification exams.

This expansion means thirteen additional Specialist and Professional certifications are now available to take online including our newest Cloud and Automation/DevOps exams.

To make sure you are able to test this way – be sure to run their simulation of the experience located here:

Click Here to Test Your Setup