ELK STACK DISK USED COMPLETELY

we can not  see the logs in  gui kibana discover.
no data in kibana dashboards.
if we see the logs all indices moved to readonly mode.


 df -h   // scheck the disk utilization
 sudo du -h /var/lib/elasticsearch/  //check the disk utilization of directories
curl -Ss -k https://admin:admin@localhost:9200/_cat/indices?v&s=store.size:desc             //   size of indices in MB
curl -Ss -k -X DELETE "https://admin:admin@localhost:9200/.monitoring-es-6-2019.*"          //    remove the indices

Execute the following statement in the kibana development console.


PUT _settings

{

"index": {

"blocks": {

"read_only_allow_delete": "false"

}

}

}

'

Router Booting process

1) POST: Power On Self Test: Used to test the router hardware

  - Then load the Bootstrap Program

2) Locate & Load IOS Software into ram

  - Bootstrap program locates the ios software and loads it into RAM.

  - IOS file located in in one of three places:

           1. flash memory (default option), 

           2. a TFTP server, 

           3. or another location indicated in the startup configuration file

3) Locate and execute the startup configuration file or enter setup mode.

  - Startup file is copied from nvrom to RAM then router is started.

Refferences:

• http://www.orbit-computer-solutions.com/Cisco-Routers-Boot-Process.php
• 
  

Multicast From Learing Series

• Unicast is destination based 
• multicast is source based
• client is application
• 
  

MISC

• Each AS contain indipenent routing policies.
• Border Gateway Protocol (BGP) is 
• an interdomain routing protocol 
• designed to provide loop-free routing between separate routing domains 
• that contain independent routing policies (autonomous systems)
• BGP is mainly used to connect a local network to an external network to gain access to the Internet or to connect to other organizations.
• BGP uses a path-vector routing algorithm to exchange network reachability information with other BGP speaking networking devices.
• Network reachability information is exchanged between BGP peers in routing updates.
• Network reachability information contains 
• the network number, 
• path specific attributes, 
• and the list of autonomous system numbers that a route must transit through to reach a destination network.
• BGP prevents routing loops 
• by rejecting any routing update that contains the local autonomous system number 
• because this indicates that the route has already traveled through that autonomous system and a loop would therefore be created. 
• The BGP path-vector routing algorithm is a combination of the 
• distance-vector routing algorithm and the AS-path loop detection.
• NULL vs LOOPBACK interfaces

Correct Answer by Paul Stewart - CCIE Security, CCSI  on Mar 14, 2011 3:56 PM

Paul Stewart  -  CCIE Security, CCSI

There is a software interface called the loopback interface.  However, there isn't really a null interface, but you can create null routes.  A null route just indicates to the router to throw packets containing a certain destination away. 

Do they offer the same function?

A loopback is used for the router ID for OSPF and EIGRP, no similar function exists with a null route.  We can bring a loopback directly into the routing process by using the "network x.x.x.x" command.  No similar command exists for null routes and a null route is not used for any type of router ID.  Either can be used for redistribution.  To redistribute a loopback, you would use the "redistribute connected".  To redistribute a null route, you would use "redistribute static".

• Asymmetric Routing: Incoming and outgoing routes are different between source & destination.

Mulit Exit Discriminator (MED)

• The name of this metric for BGP versions 2 & 3 is INTER_AS_METRIC
• MED value can be configure using Route Maps
• MED is passed between iBGP peers along with an update without any change in value.
• This action