LINHOST.INFO

Where’s My Traceroute in Ubuntu

Luis Ventura — Fri, 17 May 2013 07:44:10 +0000

By default if you try to use the traceroute command in Ubuntu it will suggest installing the application since there is no application by such name installed.

user@bicerin:~$ traceroute The program 'traceroute' can be found in the following packages: * inetutils-traceroute * traceroute Try: sudo apt-get install

While you could apt-get install traceroute your way out of it, you could instead use the included mtr application.

http://manpages.ubuntu.com/manpages/gutsy/man8/mtr.8.html

mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.

I like the way mtr presents the output instead of the normal traceroute applications, mtr constantly pings the address in a live manner and watch the output update according to network conditions.

user@bicerin:~$ mtr linhost.info

Host Loss% Snt Last Avg Best Wrst StDev 1. OpenWrt.lan 0.0% 3 0.5 0.5 0.4 0.5 0.0 2. ??? 3. te-9-2-ur01.fourhills.nm.albuq.comcast.net 0.0% 2 9.3 8.9 8.5 9.3 0.5 4. te-4-2-ar01.albuquerque.nm.albuq.comcast.net 0.0% 2 8.8 9.2 8.8 9.6 0.5 5. te-0-0-0-8-cr01.denverqwest.co.ibone.comcast.net 0.0% 2 18.0 23.1 18.0 28.3 7.2 6. he-3-12-0-0-cr01.denver.co.ibone.comcast.net 0.0% 2 21.2 21.0 20.9 21.2 0.2 7. xe-0-0-0.bbr01.cf01.den01.networklayer.com 0.0% 2 17.3 17.2 17.0 17.3 0.2 8. ae12.bbr02.eq01.dal03.networklayer.com 0.0% 2 31.8 33.0 31.8 34.2 1.7 9. po32.dsr01.dllstx3.networklayer.com 0.0% 2 31.6 31.6 31.6 31.7 0.1 10. po31.dsr01.dllstx2.networklayer.com 0.0% 2 31.9 32.4 31.9 33.0 0.8 11. po1.car14.dllstx6.networklayer.com 0.0% 2 34.8 35.1 34.8 35.3 0.4 12. gator524.hostgator.com 0.0% 2 31.9 32.8 31.9 33.7 1.3

I didn’t know about mtr which is why I decided to create this post as a reminder.

Note To Self: Copy Files Between Two Systems with Rsync

Luis Ventura — Sat, 27 Apr 2013 05:27:41 +0000

I needed to copy a couple hundred GBs of data as a precaution from a VPS to another location for temporary storage since I was about to mess with the file system. After reading the man pages and other blogs I guess this was the best I could come up with.

rsync -arz -e ssh /local_path/ remote_user@ip_address:/remote_path/

`-a`	archive mode
`-r`	recurse into directories
`-z`	compress file during the transfer
`-e ssh`	remote shell SSH

Other parmeters to add:

`--partial`	keep partially transferred files
`--delete`	delete extraneous files from destination dirs

Monitor MDADM Rebuild Progress

Luis Ventura — Tue, 05 Mar 2013 08:42:00 +0000

Just in case you find your self creating or rebuilding an MDADM array here is a simple combination that will output every two seconds the status of the array.

We combine watch and cat retrieve and update the status of the array.

watch cat /proc/mdstat

Every 2.0s: cat /proc/mdstat                            Tue Mar  5 00:34:35 2013

Personalities : [raid1]
md1 : active raid1 sdc1[1] sdb1[0]
      262011712 blocks super 1.2 [2/2] [UU]
      [>....................]  resync =  3.1% (8126080/262011712) finish=20.7min
 speed=204065K/sec

unused devices:

Configure Trunking Between Cisco Catalyst 2960 Switches

Luis Ventura — Fri, 01 Feb 2013 08:54:16 +0000

This tutorial also applies to other Cisco switches. The Cisco Catalyst 2960 is a layer 2 switch, perhaps one of the most commonly used switches I see in the field. Trunking is a solution for connecting two switches at layer 2, trunking even allows for VLANs in both switches to communicate.

For this tutorial I will create a trunk between two Cisco Catalyst 2960 switches. My Catalyst 2960 come with two gigabit uplink ports, I will use one port on each switch to establish the trunk. By default all VLANs will be able to traverse the trunk(this includes VLAN 1).

SWITCH-A Trunk Configuration

SWITCH-A# configure terminal
SWITCH-A(config)# interface gigabitEthernet 1/1
SWITCH-A(config-if)# description trunk link
SWITCH-A(config-if)# switchport mode trunk
SWITCH-A(config-if)# switchport nonegotiate

Command explanation:

switchport mode trunk - Configure interface for trunking mode
switchport nonegotiate - Since the interface was manually configure for trunking there is no need to negotiate

SWITCH-B Trunk Configuration

SWITCH-B configuration steps are identical to SWITCH-A.

SWITCH-B# configure terminal
SWITCH-B(config)# interface gigabitEthernet 1/1
SWITCH-B(config-if)# description trunk link
SWITCH-B(config-if)# switchport mode trunk
SWITCH-B(config-if)# switchport nonegotiate

Conclusion

By trunking two switches together the amount of available ports can be increased. The interfaces linking the two switches may be come bottle necks if the switches send more traffic than either the Fast Ethernet or Gigabit Ethernet port used for the trunk can handle, to increase bandwidth between the switches consider adding EtherChannel to the trunk link.

Feel free to leave a comment below, who knows I maybe able to provide some extra assistance.

Delete Multiple VLAN’s at Once – Cisco IOS

Luis Ventura — Wed, 30 Jan 2013 05:19:04 +0000

The scenario is a simple one, I have a Cisco 2960 switch with 3 VLANs(10 Acct_dept, 12 HR_dept, 20 Guests) that I need to remove. To demonstrate here is the partial output from the Catalyst 2960, use the show vlan command to view all VLANs in the switch.

SW1# show vlan

VLAN Name                             
---- -------------------------------- 
1    default                          
                                           
10   Acct_dept                        
12   HR_dept                                                  
20   Guests                       
1002 fddi-default                     
1003 token-ring-default              
1004 fddinet-default

To delete multiple VLANs(range) we use the no parameter, followed by the VLANs range to be deleted. In this case all VLANs between 10 and 20 will be removed. When you delete a VLAN ports assigned to the same will revert back to VLAN 1.

SW1(config)# no vlan 10-20

Issue the show vlan command once again to confirm that all previous VLANs are now removed.

SW1# show vlan

VLAN Name                             
---- -------------------------------- 
1    default                          
                                  
1002 fddi-default                     
1003 token-ring-default              
1004 fddinet-default

Conclusion

Efficient and less painful for those of us that regularly make changes.

Feel free to leave a comment below, who knows I maybe able to provide some extra assistance.

Creating Ethernet VLANs on Catalyst Switches – cisco.com

Disable CDP (Cisco Discovery Protocol) – Cisco IOS

Luis Ventura — Wed, 30 Jan 2013 03:20:34 +0000

CDP or Cisco Discovery Protocol is enable by default on Cisco routers, CDP can be disabled either globally (stops advertisements on all interfaces) or partially by disabling advertisements on specific interface(s).

Disable CDP Globally

R1# configure terminal

R1(config)# no cdp run

Disable CDP on Specific Interface

R1# configure terminal

R1(config)# interface fa0/0

R1(config-if)# no cdp enable

Re-enable CDP

Changed your mind, that’s ok you can re-enable CDP.

R1(config)# cdp run

Conclusion

CDP is usually disable due to security reasons people don’t like to advertise more than they have to, another good reason is CDP happens to be Cisco proprietary if the device on the other side of the interface is not Cisco then there is no reason for CDP to be running in the first place.

Feel free to leave a comment below, who knows I maybe able to provide some extra assistance.

Configuring Cisco Discovery Protocol (CDP)- cisco.com

Import OVF VM Into VMware Workstation 8

Luis Ventura — Mon, 24 Dec 2012 12:45:16 +0000

VMware Workstation can import virtual machines packaged in the OVF format, the process takes little time and is surprising easy to follow.

From VMware Workstation go to File > Open…

You are now presented with a window, on the lower right corner select Open Virtual Machine Format Images (*.ovf, *.ova) from the drop down menu.

Browse to the location where the virtual machine resides and select it, click on Open.

Now you can either choose to rename the virtual machine and modify path, the defaults work for me. Click on Import to start the process.

Look at that progress bar, be patient.

The newly imported virtual machine should now be usable in VMware Workstation.

If you have any questions leave a comment below.

Happy Holidays

Luis Ventura — Mon, 24 Dec 2012 11:17:21 +0000

Remember to stay safe and start planning how to lose those extra pounds that come with the holidays.

Cisco Continuous Ping

Luis Ventura — Wed, 28 Nov 2012 12:48:50 +0000

If you ping an address from a Cisco router the ping will be repeated five times, to increase the amount of repeated pings all you need to do is make use of the repeat parameter. The command below will ping 10.10.10.1 1000 times.

R1# ping 10.10.10.1 repeat 1000

Breakdown

ping: Execute ping
10.10.10.1: Address of the host we weill be pinging
repeat: Ping should be repeated
1000: Repeat ping 1000 times

Repeat In Action

R2# ping 10.10.10.1 repeat 1000

Type escape sequence to abort.
Sending 1000, 100-byte ICMP Echos to 10.10.10.1, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (1000/1000), round-trip min/avg/max = 1/5/8 ms

Scan a subnet with Nmap

Luis Ventura — Mon, 05 Nov 2012 07:26:26 +0000

Simple Nmap combination useful if you need to scan an entire subnet for active hosts and the IP addresses used by the same. I am not an expert on Nmap if you have a better method let me know.

1. From a command line window issue the command below.

nmap -v -sn 192.168.1.0/24

-v

Vervose

-sn

Ping scan – disable port scan

2. Nmap outputs its findings along with the IP address and MAC address of the clients on the subnet.

# nmap -v -sn 192.168.1.0/24

Starting Nmap 5.51 ( http://nmap.org ) at 2012-11-05 00:10 Mountain Standard Time
Initiating ARP Ping Scan at 00:10
Scanning 11 hosts [1 port/host]
Completed ARP Ping Scan at 00:10, 0.53s elapsed (11 total hosts)
Initiating Parallel DNS resolution of 11 hosts. at 00:10
Completed Parallel DNS resolution of 11 hosts. at 00:10, 16.50s elapsed
Nmap scan report for 192.168.1.0 [host down]
Nmap scan report for 192.168.1.1
Host is up (0.0010s latency).
MAC Address: 00:90:7F:26:3E:13 (WatchGuard Technologies)
Nmap scan report for 192.168.1.2 [host down]
Nmap scan report for 192.168.1.10 [host down]
Initiating Parallel DNS resolution of 1 host. at 00:10
Completed Parallel DNS resolution of 1 host. at 00:11, 16.50s elapsed
Nmap scan report for 192.168.1.11
Host is up.
Initiating ARP Ping Scan at 00:11
Scanning 244 hosts [1 port/host]
Completed ARP Ping Scan at 00:11, 1.96s elapsed (244 total hosts)
Initiating Parallel DNS resolution of 244 hosts. at 00:11
Completed Parallel DNS resolution of 244 hosts. at 00:11, 16.50s elapsed
Nmap scan report for 192.168.1.12 [host down]
Nmap scan report for 192.168.1.17 [host down]
Nmap scan report for 192.168.1.18
Host is up (0.0019s latency).
MAC Address: 00:0C:29:97:30:0A (VMware)
Nmap scan report for 192.168.1.19 [host down]
Nmap scan report for 192.168.1.255 [host down]
Read data files from: C:\Program Files (x86)\Nmap
Nmap done: 256 IP addresses (3 hosts up) scanned in 52.16 seconds
           Raw packets sent: 509 (14.252KB) | Rcvd: 3 (84B)