For troubleshooting purposes I find the file /var/log/inventory quite useful. You know why? If you haven’t displayed this file so far, go and run the command >show log inventory Jan 1 00:16:44 CHASSISD release 10.4R4.5 built by builder on 2011-05-06 06:19:27 UTC Jan 1 00:16:44 FPC - part number 750-111111, serial number ATXXXXXXX With this
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One of the things that I need during troubleshooting sessions is to run a specific command at regular intervals. Instead of doing this manually you can create a tiny script to run your command every second for you. Here is how you can do it; while [ 1 ] do cli -c "show route receive-protocol
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I just want to talk about briefly how you can configure a simple virtual router in Junos. For this I have drawn a physical and a logical view of my simple topology. In physical view, you can see that there is only one SRX but logically there are actually one virtual router connected from interface
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If you have two multiple equal cost paths to the same destination, JunOS behavior is to pick up one of the next-hops and use that one. For example in the following scenario, Junos keeps sending the packets via the ge-0/0/0.41 interface. root@R4> show route 172.16.1.0 inet.0: 7 destinations, 7 routes (7 active, 0 holddown, 0
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MRU (Maximum Receive Unit) has a close relation to MTU but as far as I can see it has different effects in various active devices. For example setting an MTU value of 1000 on an Ethernet interface of a Linux machine or an SRX box doesn’t prevent the larger packet from being accepted. However if
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I would like to talk about couple of things in this post about MTU on JunOS; Why do we have two different MTU settings i.e at interface and logical level? What is the meaning of path mtu discovery on a junos box How MTU is important for OSPF? Actually all started with my OSPF tests
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I will configure GRE (Generic Routing Encapsulation) between two Juniper SRX firewal devices. If you want to learn more about the protocol see RFC2784. I will just demonstrate how two networks can be connected to each other via a tunnel. I will also show how SRX security policy should be configured in order to pass
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I will briefly write about Branch SRX alarm led and reset button in this post. 1) Alarm led Today when I deleted my rescue configuration via; > request system configuration rescue delete command, then minutes later I noticed that alarm led on the front panel turned to amber. First I couldn’t guess that alarm is
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If you want to capture some icmp traffic destined for a Junos router by using “monitor traffic“, you must re-think what you are doing. For example you issued the following command and you started ping from another host towards this Junos router. admin@host> monitor traffic interface ge-0/0/1 matching "icmp or tcp" verbose output suppressed, use
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There is a very handy feature in junos which you may find very useful if you have lots of junos devices. JunOS can send your active configuration after every commit to a configured remote destination server by using scp,http or ftp protocols. A small configuration is sufficient to achieve this. For example with the configuration
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