NETWORK SIMULATORS FOR NETWORK ENGINEERS

1) GNS3

www.gns3.com

GNS3 is one of the Network Simulators, that allows you to use real router images and practice on real router CLI.
Generally it is used for Cisco devices with IOS images.
But you can also add Juniper JUNOS images, and you can use this devices on your simulated network.

GNS3 is especially an important network simulator for you during your certification studies.
For Cisco CCNA, CCNP, CCIE or For Juniper JNCIA, JNCIP, JNCIE .


2) Cisco Packet Tracer

www.netacad.com

 
Cisco Packet Tracer is the other example of Network Simulators, in which there are many routers, switches and various network devices. You can build your topology with Packet Tracer and you can configure Cisco IOS based devices easily.


Cisco Packet Tracer is developed by Cisco Systems and it is especially very good tool for Cisco Network Certification studies.  With Packet Tracer, you can practice on Cisco Routers, switches, Access Points etc. It is  especially perfect configuration practice tool for beginner network engineers.

3) EVE-NG

 www.eve-ng.net

 

EVE-NG (Emulated Virtual Environment) is an important platform with which you can practice on network device with various topologies. 

It is a strong Network Emulation Program and one of the Network Simulators for both companies or individuals. 

4) Cisco VIRL

 virl-dev-innovate.cisco.com

 

Cisco VIRL is the useful and powerful network simulation platform of Cisco.

With Cisco VIRL, you can model your network with Cisco VIRL and you can practice on Cisco devices with this excellent Network Simulator Program.

Thanks for Reading !!!!!!

amartechstuff

5 Online Internet Tools for Network Engineer

Online tools !!!!!!!!!!!!!!!!!!!!!!!!!!

They are important for any ISP Engineer who need to check Internet related stuff.

Below are the few Online Internet tools you must try !

1) https://ping.eu

2) https://www.locaping.com

3) https://www.robtex.com

 

4) https://centralops.net/co/

 


5) https://mxtoolbox.com/SuperTool.aspx

 

 
Thanks for Reading !!!!!

amartechstuff

Best Online Sites to Create Network Diagram

1)https://app.diagrams.net

The best Online site to prepare Network Diagram
Here you can save diagram to all kinds on Internet online drivers.
It is completely free to use for any purpose, there is no premium pay-for functionality, watermarking, or other limitations. You own the content you produce with draw.io and may use it for any purpose, including commercially.

2)https://www.smartdraw.com

It is also a good online site which provides desktop version, not free.
For Cloud , trial for only 7 days, no free usage.

3)https://www.lucidchart.com/

It can import /export visio format file. Free account will limit complexity to only 60 objects, three active documents, 25mb of Storage, not able to edit imported visio files, etc.

4)https://www.gliffy.com/

After trial, it is still free to use, but not able to create a new diagram. Existing diagrams will still be kept for editing. Gliffy marks all diagrams as public when a trial expires. Any diagrams created would remain in the account. Diagrams always remain in the account regardless of the status. Gliffy never moves or deletes diagrams. Free account have a limit of 2MB or 5 diagrams, but usually it is enough since you export to gliffy format to import it later.

5) https://www.cloudcraft.co/

Best online site to create AWS diagrams .

 

 

 

Thanks for reading

amartechstuff

Broadcast Ping !!!

 If you want to ping all the subnets / networks/links configured on the router in one command !!

There is a way !!!!!!!!

Broadcast Ping 

 

 

Here Router 1 have 3 different links / networks .

So lets try ping all the hosts & links in one command

R1#ping 255.255.255.255

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 255.255.255.255, timeout is 2 seconds:

Reply to request 0 from 12.1.1.2, 2 ms

Reply to request 0 from 10.1.1.100, 2 ms

Reply to request 0 from 10.1.1.200, 2 ms

Reply to request 0 from 13.1.1.3, 12 ms

Reply to request 1 from 12.1.1.2, 1 ms

Reply to request 1 from 13.1.1.3, 1 ms

Reply to request 1 from 10.1.1.100, 2 ms

Reply to request 1 from 10.1.1.200, 2 ms

Reply to request 2 from 12.1.1.2, 1 ms

Reply to request 2 from 10.1.1.100, 1 ms

Reply to request 2 from 10.1.1.200, 1 ms

Reply to request 2 from 13.1.1.3, 1 ms

Reply to request 3 from 10.1.1.100, 1 ms

Reply to request 3 from 10.1.1.200, 1 ms

Reply to request 3 from 12.1.1.2, 1 ms

Reply to request 3 from 13.1.1.3, 2 ms

Reply to request 4 from 12.1.1.2, 1 ms

Reply to request 4 from 10.1.1.100, 1 ms

Reply to request 4 from 10.1.1.200, 1 ms

Reply to request 4 from 13.1.1.3, 1 ms

R1#

 By using the Broadcast ping !! You can see that we have successfully pinged all the host and links present on the router!

I hope this will really help you all and save your valuable time !!

Thanks for Reading !!!

amartechstuff

 

 

Broadcast Ping !!!! From Router

This article we are going to see how we can use Broadcast Ping from Router to ping all the networks/subnets configured on  the routers .!!!!!!

This command will definitely help lot of Network Engineer who check status of all the links in one command.

 

R1#sh ip int brief | ex una
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            12.1.1.1        YES NVRAM  up                    up
FastEthernet0/1            13.1.1.1        YES manual up                    up

The Router have 2 Wan interfaces !!!!

R1#ping 255.255.255.255

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 255.255.255.255, timeout is 2 seconds:

Reply to request 0 from 12.1.1.2, 12 ms
Reply to request 0 from 13.1.1.3, 12 ms
Reply to request 1 from 12.1.1.2, 112 ms
Reply to request 1 from 13.1.1.3, 148 ms
Reply to request 2 from 12.1.1.2, 72 ms
Reply to request 2 from 13.1.1.3, 144 ms
Reply to request 3 from 13.1.1.3, 60 ms
Reply to request 3 from 12.1.1.2, 68 ms

Thanks for Reading

amartechstuff

 

 

EIGRP Quick Configuration

 If there are many interfaces /networks on the Routers running EIGRP and you wish to advertise all of those in EIGRP then there is no point of advertising individual routes in eigrp 

Use quick way of EIGRP configuration. 

R1#sh ip protocols

R1#

R1#sh run | section eigrp
R1#

R2#sh ip protocols

R2#
R2#sh run | section eigrp
R2#


R1(config)#router eigrp 100
R1(config-router)#network 0.0.0.0 0.0.0.0
R1(config-router)#exit
R1(config)#exit
R1#

R2(config)#router eigrp 100
R2(config-router)#network 0.0.0.0 0.0.0.0
R2(config-router)#exit
R2(config)#
*Mar  1 00:23:14.851: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 12.1.1.1 (FastEthernet0/0) is up: new adjacencyexit
R2#


R1#sh ip ei neighbors
IP-EIGRP neighbors for process 100
H   Address                 Interface       Hold Uptime   SRTT   RTO  Q  Seq
                                            (sec)         (ms)       Cnt Num
0   12.1.1.2                Fa0/0             14 00:00:27   24   200  0  3

R2#sh ip ei neighbors
IP-EIGRP neighbors for process 100
H   Address                 Interface       Hold Uptime   SRTT   RTO  Q  Seq
                                            (sec)         (ms)       Cnt Num
0   12.1.1.1                Fa0/0             10 00:00:40   18   300  0  4


R1#sh ip protocols
Routing Protocol is "eigrp 100"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Default networks flagged in outgoing updates
  Default networks accepted from incoming updates
  EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
  EIGRP maximum hopcount 100
  EIGRP maximum metric variance 1
  Redistributing: eigrp 100
  EIGRP NSF-aware route hold timer is 240s
  Automatic network summarization is in effect
  Automatic address summarization:
    100.0.0.0/8 for FastEthernet0/0
      Summarizing with metric 128256
    12.0.0.0/8 for Loopback100
      Summarizing with metric 281600
  Maximum path: 4
  Routing for Networks:
    0.0.0.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    (this router)         90      00:03:27
    12.1.1.2              90      00:01:29
  Distance: internal 90 external 170

R1#

R2#sh ip protocols
Routing Protocol is "eigrp 100"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Default networks flagged in outgoing updates
  Default networks accepted from incoming updates
  EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
  EIGRP maximum hopcount 100
  EIGRP maximum metric variance 1
  Redistributing: eigrp 100
  EIGRP NSF-aware route hold timer is 240s
  Automatic network summarization is in effect
  Automatic address summarization:
    200.200.200.0/24 for FastEthernet0/0
      Summarizing with metric 128256
    12.0.0.0/8 for Loopback200
      Summarizing with metric 281600
  Maximum path: 4
  Routing for Networks:
    0.0.0.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    (this router)         90      00:01:59
    12.1.1.1              90      00:01:57
  Distance: internal 90 external 170

R2#

R1#sh ip ei topology
IP-EIGRP Topology Table for AS(100)/ID(100.100.100.100)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

P 100.100.100.100/32, 1 successors, FD is 128256
        via Connected, Loopback100
P 12.0.0.0/8, 1 successors, FD is 281600
        via Summary (281600/0), Null0
P 12.1.1.0/24, 1 successors, FD is 281600
        via Connected, FastEthernet0/0
P 100.0.0.0/8, 1 successors, FD is 128256
        via Summary (128256/0), Null0
P 200.200.200.0/24, 1 successors, FD is 409600
        via 12.1.1.2 (409600/128256), FastEthernet0/0
R1#


R2#sh ip eigrp topology
IP-EIGRP Topology Table for AS(100)/ID(200.200.200.200)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

P 200.200.200.200/32, 1 successors, FD is 128256
        via Connected, Loopback200
P 12.0.0.0/8, 1 successors, FD is 281600
        via Summary (281600/0), Null0
P 12.1.1.0/24, 1 successors, FD is 281600
        via Connected, FastEthernet0/0
P 100.0.0.0/8, 1 successors, FD is 409600
        via 12.1.1.1 (409600/128256), FastEthernet0/0
P 200.200.200.0/24, 1 successors, FD is 128256
        via Summary (128256/0), Null0
R2#

R1#sh ip route eigrp
D    200.200.200.0/24 [90/409600] via 12.1.1.2, 00:02:14, FastEthernet0/0
     100.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D       100.0.0.0/8 is a summary, 00:04:11, Null0
     12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D       12.0.0.0/8 is a summary, 00:04:11, Null0
R1#
R1#
R1#ping 200.200.200.200

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.200.200.200, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/10/16 ms
R1#

R2#sh ip route eigrp
     200.200.200.0/24 is variably subnetted, 2 subnets, 2 masks
D       200.200.200.0/24 is a summary, 00:02:57, Null0
D    100.0.0.0/8 [90/409600] via 12.1.1.1, 00:02:55, FastEthernet0/0
     12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D       12.0.0.0/8 is a summary, 00:02:57, Null0
R2#
R2#ping 100.100.100.100

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.100.100.100, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/16/32 ms
R2#

Thanks for reading !!!!!

amartechstuff

 

BGP CHAPTER 19 - BGP PATH SELECTION

 In BGP Table – If there are multiple paths to reach a destination network then BGP PATH SELECTION comes into picture.

 

 

 

Unlike other Routing Protocol it is very different 

Can’t Compare with IGPs –RIP , OSPF , EIGRP 

BGP ATTRIBUTES PLAYS A VERY IMPORTANT ROLE

 BGP PATH SELECTION MNEMONIC 

“We Love Oranges AS Oranges Mean Pure Refreshment”

 

 BGP PATH SELECTION

 Condition :- The route should have valid Next hop then it will consider for BGP Path Selection.

Highest Weight is preferred.(local to the router)

Highest Local Preference is preferred.

Locally Originate routes are preferred.

Shortest AS Path is preferred.

Lowest Origin code is preferred.

Lowest MED value is preferred.

Path - EBGP is preferred over IBGP.

The path with the lowest BGP neighbor Router ID . 

Few more ………….  

The path within the AS with the lowest IGP metric to the BGP next hop

Oldest Path – the path that was received first

The path with the lowest neighbor IP address.

 

Thanks for Reading 

amartechstuff