Some Things I've learnt about GNS3

I am in no way an expert on GNS3, just a trainee   below are a few things i have learnt lately. I thought it might be a good idea to produce something like this. If everyone replied to it and added a few tips of their own it could be turned into a CLN GNS3 tips and tricks document.

GNS3 Web Sites
http://www.gns3.net GNS3’s primary Web site
http://wiki.gns3.net GNS3’s Wiki site
http://www.ipflow.utc.fr/index.php/Cisco_7200_Simulator Dynamips – the actual emulator

http://www.ipflow.utc.fr/blog/ Dynamips blog
http://dyna-gen.sourceforge.net/ Dynagen
http://www.ipflow.utc.fr/bts/ Dynamips/Dynagen bug tracking
http://7200emu.hacki.at Hacki’s forum
===

1. GNS3 has less chance of crashing if the bin files are unzipped.

2. Currently images for 2600 routers must be uncompressed to work with Dynamips.

3. To dramatically reduce the load on your processor, right click on the router and choose idle, after a few moments it will give you a list to choose from.
Choose the one with a * against it, if you don't see a * in the choice run it again.

4. If you don't need any special routers then use the same type on the whole lab, this will use far less processing power and memory.

5. To print out the diagram of your network click file then export, you can export all or just what is visible.

6. To move your router/routers/links etc click the left mouse button and draw around what you want to move, you can then move everything that is inside that shape.

7. I find that if you move around the interface identities they eventually go back to their original position. I don't move them anymore as it looks a bit
messy when that happens.

8. You can't use GNS3 for the SWITCH studies, GNS3 only has basic switch capabilities.

9. You can create computers and run ping's/telnet with VPC, the document attached shows you how, its very simple to follow. I did find that it takes a few times for it to accept being a cloud, once you click ok just open it back up and check it.

10. I personally find that it is best to connect your links between routers when they are switched off, sometimes i find it fails otherwise.

11. You can create a router to act like a pc, this is shown below but it is also in the document.

Router(config)# no ip routing         Turns off IP routing function
Router(config)# interface fa0/0      Switches to FastEthernet interface
Router(config-if)# ip address address subnet_mask Assigns IP address and subnet mask to interface
Router(config-if)# no shutdown      Turns interface on
Router(config-if)# exit                     Returns to global configuration mode
Router(config)# ip default-gateway gateway_address Configures the default gateway
Router(config)# ip http server         Optional – starts http server process
===

12. You can connect GNS3 to real equipment, i have not done this yet myself, it is in the document attached how to do this.

13. When using windows 64 bit GNS3 will default to program files (x86). GNS3 is a 32 bit program for windows so point it to program files not the (x86).

14. I have a Lenovo Thinkpad with a i7 processor and 4GB of RAM. With 7 routers of the same type my processor is running between 8 and 15 %, my RAM consumption is around 2.3 to 2.8 GB. That is also using a few other programs on my laptop at the sometimes.

How Update DNS Records in Local Linux Machine - [ Ubuntu ]

Created Thursday 28 August 2014

By TDL Matias

***************************************************************
This tutorial is to use as my own keep track record of things I do everyday with Linux.. I had to install a new linux distro into a user computers, the distro in question was Ubuntu 12.04 - 64bit.

I have gave the machine a name = DevOps14 with IP 172.xx.xx.184 - The problem is that that same machine, had being installed on the intranet before with same hostname (DevOps14) and had assigned previously the IP address 172.xx.xx.185 ..

after installed, I tried to access it using the hostname, I was getting network names conflit errors ..

When I tried to ping it .. I was getting the following error ...


user@host1:~$ traceroute -n devops14.uk.domain
traceroute to devops14.uk.domain (172.xx.xx.185), 30 hops max, 60 byte packets
1 172.16.14.70 2996.257 ms !H 2996.201 ms !H 2996.180 ms !H

user@host1:~$ ping -c 3 devops14.uk.domain
PING devops14.uk.domain(172.xx.xx.185) 56(84) bytes of data.
From host1.uk.domain (172.xx.xx.xx) icmp_seq=1 Destination Host Unreachable
From host1.uk.domain (172.xx.xx.xx) icmp_seq=2 Destination Host Unreachable
From host1.uk.domain(172.xx.xx.xx) icmp_seq=3 Destination Host Unreachable


--- devops14.uk.domain ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2014ms


Then, I went and updated our DNS server records usind rndc tool ... Tried do ping the devops14 again .. but not avail ..


user@host1:~$ ping -c 3 devops14.uk.domain
PING devops14.uk.domain (172.xx.xx.185) 56(84) bytes of data.
From host1.uk.domain (172.xx.xx.xx) icmp_seq=1 Destination Host Unreachable
From host1.uk.domain (172.xx.xx.xx) icmp_seq=2 Destination Host Unreachable
From host1.uk.domain (172.xx.xx.xx) icmp_seq=3 Destination Host Unreachable


---devops14.uk.domain ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2000ms
pipe 3


Ok then ..IF I have updated the DNS - Records, theres no reason that I could not ping that machine right into the IP - 172.xx.xx.184 instead of 172.xx.xx.185 ... Something was no really adding up ...


So I went into https://www.google.com/ to investigate and se if someone had come accross the same issue it was then when I found in a Ubuntu forum [http://askubuntu.com/questions/414826/how-to-flush-dns-in-ubuntu-12-04 ]


That I had only to refresh the network DNS record on my local machine with this command.


user@host1:~$ sudo /etc/init.d/nscd restart
* Restarting Name Service Cache Daemon nscd                                                                      [ OK ]


And then PING it again ....


user@host1:~$ ping -c 3 devops14.uk.domain
PING devops14.uk.domain (172.xx.xx.184) 56(84) bytes of data.
64 bytes from devops14.local (172.xx.xx.184): icmp_seq=1 ttl=64 time=0.582 ms
64 bytes from devops14.local (172.xx.xx.184): icmp_seq=2 ttl=64 time=0.139 ms
64 bytes from devops14.local (172.xx.xx.184): icmp_seq=3 ttl=64 time=0.103 ms


---devops14.uk.domain ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2000ms rtt min/avg/max/mdev = 0.103/0.274/0.582/0.218 ms



 All working fine now ... 

How to Allow MySQL Client to Connect to Remote MySQL server

Issue: How do I allow a MySQL client to connect to a MySQL database server?

Solution: By default, MySQL does not allow remote clients to connect to the MySQL database.
If you try to connect to a remote MySQL database from your client system, you will get the “Host is not allowed to connect to this MySQL server” message as shown below.

$ mysql -h 192.168.1.8 -u root -p
Enter password:
ERROR 1130: Host '192.168.1.4' is not allowed to connect to this MySQL server

You can also validate this by doing telnet to 3306 mysql port as shown below, which will also give the same “host is not allowed to connect to this MySQL server” error message.

$ telnet 192.168.1.8 3306
host 192.168.1.4 is not allowed to connect to this mysql server

If you want to allow a specific client ip-address (for example: 192.168.1.4) to access the MySQL database running on a server, you should execute the following command on the server that is running the MySQL database.

$ mysql -u root -p
Enter password:
mysql> use mysql
mysql> GRANT ALL ON *.* to root@'192.168.1.4' IDENTIFIED BY 'your-root-password';
mysql> FLUSH PRIVILEGES;

Also, update firewall rules to make sure port# 3306 is open on the server that is running the MySQL database.


After the above changes, when you try to connect to the MySQL database from a remote client, you’ll not get the “Host is not allowed to connect to this MySQL server” error message any more.

How Edit MySQL connection Error

    Cannot connect to MySQL server over network

Check /etc/my.cnf and make sure you are listening for outside connections. edit the line that starts with bind-address

change:

Code:

bind-address = 127.0.0.1

to:

Code:

#bind-address = 127.0.0.1

make sure mysql is running:

Code:

/etc/init.d/mysql status

if not, start it:

Code:

/etc/init.d/mysql start

check if the ubuntu firewall is running

Code:

sudo ufw status

if it is, allow mysql

Code:

sudo ufw allow mysql

    **************************************************************************

Possibly a security precaution. You could try adding a new administrator account: mysql> CREATE USER 'monty'@'localhost' IDENTIFIED BY 'some_pass'; mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost' -> WITH GRANT OPTION; mysql> CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass'; mysql> GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%' -> WITH GRANT OPTION; Although as Pascal and others have noted it's not a great idea to have a user with this kind of access open to any IP. If you need an administrative user, use root, and leave it on localhost. For any other action specify exactly the privileges you need and limit the accessibility of the user as Pascal has suggest below. From the MySQL FAQ: If you cannot figure out why you get Access denied, remove from the user table all entries that have Host values containing wildcards (entries that contain '%' or '_' characters). A very common error is to insert a new entry with Host='%' and User='some_user', thinking that this allows you to specify localhost to connect from the same machine. The reason that this does not work is that the default privileges include an entry with Host='localhost' and User=''.  Because that entry has a Host value 'localhost' that is more specific than '%', it is used in preference to the new entry when connecting from localhost! The correct procedure is to insert a second entry with Host='localhost' and User='some_user', or to delete the entry with Host='localhost' and User=''. After deleting the entry, remember to issue a FLUSH PRIVILEGES statement to reload the grant tables. See also Section 5.4.4, “Access Control, Stage 1: Connection Verification”.

Having Problems to restart uBuntu 12.04 LTS workstation

Yesterday I have installed Ubuntu 12.04 on one of my testing workstations, orignally it came with Windows 7 pre-installed 2 SSD disks in a fake software Raid...

I have totatly removed Windows 7, deleted the partition and installed Ubuntu 12.04 LTS .. But, after installing Ubuntu the machine boots but do not show any signal of ubuntu ..

Its just a dark screen .. I tried to use live CD to repair the grub but with not avail...

Here is what I have from Ubuntu Boot repair tool --- >> I have taken off the script and guide to troubleshoot the ubuntu bootup, instead, I have place them into a file and you can download from and read it locally

Its hosted on Google drive here please download it !!...