Internet routing table and damping on JunOS

To get an idea about the current number of Internet routes, for both IPv4 and IPv6:

moghaddas@USA> show route summary | match "inet|bgp"  
 
inet.0: 560133 destinations, 1663174 routes (558798 active, 0 holddown, 1525 hidden)
                 BGP: 1663124 routes, 558752 active
 
inet6.0: 24047 destinations, 47458 routes (23459 active, 0 holddown, 851 hidden)
                 BGP:  47444 routes,  23447 active

Now, imagine what would be the outcome of route flaps for a Service Provider environment with many eBGP neighbors. Instability and customer dissatisfaction!

The first solution to avoid such situations is BGP Route Dampening/Damping. Continue reading “Internet routing table and damping on JunOS”

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HowTo : Logging to terminal on JunOS

In Cisco IOS, if you had logging configured, by default you could see logs on console, or using terminal monitor with a terminal connection.

It’s almost the same with JunOS. You have to get your logging parameters configured and then entering monitor start LOG_FILENAME

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How-To: Destination NAT in JunOS

You are asked to publish a local website on an external network such as Internet, and you have to do it in a secure manner using the SRX firewall at your office.

The procedure is pretty straight forward.

  1. Local host’s zone (Local IP) : show route and show interface
  2. Find out to which External (Global) IP address you should apply the D-NAT
  3. External access zone (Global IP) : show route and show interface
  4. OPTIONAL: Create “security address-book global” entries for source/destination addresses
  5. If you are Port-Forwarding: Create an “application
  6. Define a “security policy from EXTERNAL zone to LOCAL zone, matching the source (external hosts), destination (local hosts) and application (local hosts’ protocol/port) parameters and then set the action as permit
  7. Create a “NAT Destination Pool” for the Local IP and if Port Forwarding add the service’s port
  8. Define a “security nat destination rule-set rule” matching the source (external hosts), destination (local hosts) and destination-port (local hosts’ port) parameters and then set the “destination-nat pool” to the pool created in last step

Below you will find a sample snippet of the configuration:

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