Posts Tagged ‘cisco’

Secure Site-to-Site VPN tunnel using the ASA

Sunday, April 8th, 2012

Site to Site VPN enables an encrypted connection between private networks over a public network (i.e. the Internet).

Basic steps to configure a site-to-site VPN with a Cisco ASA begin with defining the ISAKMP Policy. An ISAKMP/IKE policy defines how a connection is to be created, authenticated, and protected. You can have multiple policies on your Cisco ASA. You might need to do this if your ASA needs to connect to multiple devices with different policy configurations.

  • Authentication: specifies the method to use for device authentication
  • Hash: specifies the HMAC function to use
  • Encryption: specifies which algorithm to use
  • Group: specifies the DH key group to use

Next, you will need to establish IPsec transform set. Different Firmware versions and different Cisco devices have different options for the following…

  • Esp-md5-hmac: ESP with the MD5 (HMAC variant) authentication algorithm
  • Esp-aes: ESP with the 128-bit Advanced Encryption Standard (AES) encryption algorithim.
  • Esp-des: ESP with the 56-bit Data Encryption Standard (DES) encryption algorithm.
  • Esp-3des: ESP with the 168-bit DES encryption algorithm (3DES or Triple DES)
  • Ah-md5-hmac: AH with the MD5 (HMAC variant) authentication algorithm
  • Ah-sha-hmac: AH with the SHA (HMAC variant) authentication algorithm

3. Configure crypto access list-

Crypto ACL’s are used to identify which traffic is to be encrypted and which traffic is not. After the ACL is defined, the crypto maps use the ACL to identify the type of traffic that IPSec protects.

It’s not recommended to use the permit ip any any command. It causes all outbound traffic to be encrypted, and sends all traffic to the specified peer.

4. Configure crypto map

Used to verify the previously defined parameters

5. Now apply crypto map to the outside interface.


Configuration of ASA-1

You might have to enable ISAKMP on your device

ASA-1(config)#crypto isakmp enable

First defined the IKE polices on ASA-1

ASA-1(config)#crypto isakmp policy 10

The lower the policy number, the higher the priority it will set the ISAKMP policy to, affecting which policies will be used between sites.

General rule of thumb is to give the most secure policy the lowest number (like 1) and the least secure policy the highest number (like 10000)

ASA-1(config-isakmp)#encryption des

(enable encryption des)

ASA-1(config-isakmp)#hash md5

(enable algorithm md5 for hashing)

ASA-1(config-isakmp)#authentication pre-share

(enable Pre-shared method)

ASA-1(config-isakmp)#group 2

(enable group 2)


(Exit from crypto isakmp mode)

  • The next step is to create a pre-shared key (password) on ASA-1.

ASA-1(config)#crypto isakmp key office address

(Here the Key is “office” and is ASA-2 Address)

  • Now create an access list to define only interesting traffic.

ASA-1(config)#access-list 100 permit ip host host

(100 is access list number and is source address and is destination address.)

  • Now create the transform-set for encryption and hashing.

ASA-1(config)#crypto ipsec transform-set ts2 esp-des esp-md5-hmac

(Here encryption type is des and hashing method is md5-hmac)

ASA-1(config)#crypto map testcryp 10 ipsec-isakmp

(crypto map name testcryp)

ASA-1(config)# crypto map testcryp 10 match address 100

(apply the access list)

ASA-1(config)# crypto map testcryp 10 set transform-set ts2

(apply the transform set)

ASA-1(config)# crypto map testcryp 10 set peer

(Set remote peer address)

  • Now apply the crypto map to the ASA – A interface

ASA-1(config)# crypto map testcryp interface outside

(Apply crypto map on outside interface)

ASA-1(config)# crypto isakmp enable outside

(To enable crypto isakmp on ASA)

Configuration of ASA-2

First defined the IKE polices on ASA-2

ASA-2(config)#crypto isakmp policy 10

(10 is isakmp policy number)

ASA-2(config-isakmp)#encryption des

(enable encryption des)

ASA-2(config-isakmp)#hash md5

(enable algorithm md5 for hashing)

ASA-2(config-isakmp)#authentication pre-share

(enable Pre-shared method)

ASA-2(config-isakmp)#group 2

(enable diffie-Helman group 2)


(Exit from crypto isakmp mode)

  • The next step is to create a pre-shared key (password) on ASA – B.

ASA-2(config)#crypto isakmp key office address

(Here Key is “office” and is ASA – A Address)

  • Now create an access list to define only interesting traffic.

ASA-2(config)#access-list 100 permit ip host host

(100 is access list number and is source address and is destination address.)

  • Now create the transform-set for encryption and hashing.

ASA-2(config)#crypto ipsec transform-set ts2 esp-des esp-md5-hmac

(Here encryption type is des and hashing technique is md5-hmac)

ASA-2(config)#crypto map testcryp 10 ipsec-isakmp

(crypto map name testcryp)

ASA-2(config)# crypto map testcryp 10 match address 100

(apply the access list)

ASA-2(config)# crypto map testcryp 10 set transform-set ts2

(apply the transform set)

ASA-2(config)# crypto map testcryp 10 set peer

(Set remote peer address)

  • Now apply the crypto map to the ASA – B outside interface

ASA-2(config)# crypto map testcryp interface outside

(Apply crypto map on outside interface)

ASA-2(config)# crypto isakmp enable outside

(To enable crypto isakmp on ASA)

Now to verify the secure tunnel, ping to other remote location.

ASA-2(config)# ping

Setting up Netboot helpers on a Cisco device

Tuesday, April 3rd, 2012

Configure a Cisco device for forwarding bootp requests is a pretty straightforward process. First off, this will only apply to Cisco Routers and some switches. You will need to verify if you device supports the IP Helper command. For example, the Cisco ASA will not support bootp requests.

By default the IP Helper command will forward different types of UDP traffic. The two important ones 67 and 68 for DHCP and BOOTP requests. Other ports can be customized to forward with some other commands as well. But it is quite simple pretty much if you have a Netboot server you can configure the IP Helper command to point that servers IP address.

Here is an example, lets say your NetBoot server has an IP Address of You would simply go into the global configuration mode switch to the interface you want to utilize and type “ip helper-address″ to simply relay those requests to that address. Depending on your situation you also might want to setup the device to ignore BOOTP requests (in cases that you have DHCP and BOOTP on the same network). That command is “ip dhcp bootp ignore”. Using the IP helper and Bootp ignore command together will ensure that those bootp requests are forwarded out the interface to the specified address.

Last if you have multiple subnets you can setup multiple IP Helper address statements on your device to do multiple forwarding.

Using Nagios NIBs with ESX

Thursday, March 22nd, 2012

What is a MIB

A MIB is a Management Information Base. It is an index based upon a network standard that categorizes data for a specific device so that SNMP servers can read the data.

Where to Obtain VMware vSphere MIBs

VMware MIBs are specific to VMware Version, you can try to use the ESX MIBs for ESXi. They can be downloaded from Click on VMware vSphere > find the version of ESX that you are running under “Other versions of VMware vSphere” (the latest version will be the page that you’re on). Click on “Drivers & Tools”. Then click on “VMware vSphere x SNMP MIBs” where “x” is your version.

How to add VMware vSphere MIBs into Nagios

  • Download the VMware vSphere MIBs from
  • Copy the MIB files to /usr/share/snmp/mibs/
  • Run check_snmp -m ALL so it detects the new MIBs

Editing snmpd.conf and starting snmpd on ESX

  • Stop snmpd: service snmpd stop
  • Backup snmp.xml: cp /etc/vmware/snmp.xml /etc/vmware/snmp.xml.old
  • Edit snmp.xml with your favorite CLI text editor to have the following:


  • Backup snmpd.conf: cp /etc/snmp/snmpd.conf /etc/snmp/snmpd.conf.old
  • Use your favorite CLI text editor and edit /etc/snmp/snmpd.conf
  • Erase everything in it.
  • Add in the following and save it:

load  99 99 99
syslocation ServerRoom
syscontact  “ESX Administrator”
rocommunity  public
view systemview included .
proxy -v 1 -c public .

  • Change “syslocation” and “syscontact” to whatever you want
  • Save your work
  • Configure snmpd to autostart: chkconfig snmpd on
  • Allow SNMP through firewall: esxcfg-firewall –e snmpd
  • Start the SNMP daemon: service snmpd start
  • Restart the mgmt-vmware service: service mgmt-vmware restart

Determining OID

OID’s are MIB specific variables that you can instruct an SNMP server monitor to look for. These variables can be determined by reading the MIBs. One tool that assists with doing this is MIB Browser by iReasoning Networks MIB Browser can run on Windows, Mac OS X, and Linux/UNIX. To obtain the appropriate OID’s:

  • Load the MIBs in MIB Browser by going to File > Load Mibs
  • Manually comb through to find the OID you want (it will be connected to a string that will be similar to wording used in VSphere).


  • SNMP MIBs was downloaded from for ESX 4.1
  • Loaded MIB for VMWARE-RESOURCES-MIB into MIB Browser
  • Searched for “Mem” (Edit > Find in MIB Tree), found “vmwMemAvail”, the OID for this is . (use the OID shown in the dropdown that is near the menu in the MIB Browser – it will show the full OID which will sometimes include a “0″ at the end that the OID listed towards the bottom of the window will not)
  • Add OID into remotehost.cfg (or linux config file) file in Nagios

define service{
use             generic-service ; Inherit values from a template
host_name           ESX4_1
service_description  Memory Available
check_command       check_snmp!-C public -o . -m all

host_name: the name of the device (whatever you want to call it)
service_description: the name of the service you are monitoring (whatever you want to call it)
check_command: -C is to define the community SNMP string, -o is to define the OID to read, -m is to define which MIB files to load – to be more specific, for this example you can narrow “-m all” to “-m VMWARE-RESOURCES-MIB.MIB”

Once you’ve done the above you should be able to monitor “Memory Available” for ESX through Nagios.  Repeat the procedure, changing steps where applicable for the specific OID you want to monitor.  If you have questions, or need assistance, please contact 318, Inc. at 1-877-318-1318.

Adding incoming and outgoing access rules on a Cisco ASA

Saturday, March 17th, 2012

To understand incoming and outgoing rules there are a couple of things to know before you can define your rules. Let’s start with an understanding of traffic flow on an ASA. All incoming rules are meant to define traffic that come inbound to the ASA’s interface. Outgoing is for all traffic that is going outbound of an ASA’s interface. It does not matter which interface it is since this is a matter data flow and each active interface on an ASA will have it’s own unique address.

To try an explain this further let’s say we have and internal interface with an IP address of that is for your local area network to connect to. You can add a permit or deny rule to this interface specifying whether incoming or outgoing  traffic will be permitted or not. This allows you to control what computers can communicate past that interface or not. Essentially you would define most of your rules for the local area network on the internal interface, governing which systems/devices could access the internet, certain protocols, or not.

Now if you know about the basic configuration of an ASA you know that you have to set the security level of the Internal and External ports. So by default these devices allow traffic from a higher security interface to a lower security interface. NAT/PAT will need to be configured depending on if you want to define port traffic for specified protocols.

For this article I will just mention that their are several types of Access Control Lists (ACL) that you can create on an ASA. These types are Standard, Extended, Ethertype, webtype, and IPV6. For this example we will use Extended because most likely that is what most everyone will use the most. With extended ACL not only can you specify IP addresses in the access control list, but you can specify port traffic to match the protocol that might be required.

Lets look at the the examples below:

You will see we are in the configuration terminal mode

ASA(config)# access-list acl extended permit tcp any host eq 80

-So the first part “access-list acl” means the access list will be named “acl”.
-Next you have a choice between type of access list. We are using Extended for this example.
-The next portion is the permit or deny option and we have permit selected for this statement.
-On the next selection that say’s “any” this refers to inside traffic (simply meaning that any internal traffic is allowed). If you dont use any you can specify specific devices by using “host and the IP address like that last part of this ACL statement.
-The next part of this refers to specifying a specific host address of equals port 80.

So this example tells us that our access control list named ACL will allow any inside traffic out the host address of that is internet traffic.

Later you will notice that your statement will look like this on the ASA

ASA(config)access-list acl extended permit tcp any host www
Notice how “eq 80″ default http traffic changed automatically to www) This is common on Cisco ASA devices).

Lost a password to your Cisco Device and need to recover the settings?

Friday, March 9th, 2012

Most of us know that Cisco can be a bit complicated and sometimes things happen that are not so forgiving. One of those is losing a password on a Cisco device. The downside to this is if you did not know that you could reset the password using a console cable you might be freaking out thinking you might have to reset to factory defaults. Well thank you Cisco for providing a backdoor to their devices. Now for each device the commands and procedures can be slightly different, so you will want to look up from Cisco the password recovery steps for you specific device. In the example I will show you the steps on how to reset the password on a Cisco ASA 5505 using Terminal from a Macbook.

First thing you will need to have on all the Cisco devices is Console port access. For this reason it is important to ensure there are strict physical security measures in place. Access to the device allows someone to have access to the procedures that I am about to list, which can give them unwanted entry to your device.

1.Connect to the device using the console port\cable. The cable is usually an RJ45 to Serial so on my Macbook I don’t have a serial port so I use a serial to USB adapter. All my configurations are than done in terminal. If you’re on a PC you can use your telnet application or the MS-DOS CMD window.

Using a Macbook with the serial to USB adapter requires I use the “Screen /dev/tty.KeySerial1 9600” command to be able to use terminal as my telnet window. This will allow you to view the bootup of the device as soon as it has power.

2. Now shutdown the ASA, and power it back up. During the startup messages, press and hold the “Escape” key when prompted to enter ROMMON.

3. To update the configuration register value, enter the following command:

rommon #1> confreg 0x41

4. To have the ASA ignore the startup configuration during its startup, enter the following command

rommon #1> confreg

The ASA will display the current configurations register value, and will prompt you to change the value:

Current Configuration Register: 0x00000011
Configuration Summary:
boot TFTP image, boot default image from Flash on netboot failure
Do you wish to change this configuration? y/n [n]:

5. Take note of the current configuration register value (it will be used to restore later). At the prompt enter “Y” for yes and hit enter.

The ASA will prompt you for new values.

6. Accept all the defaults, except for the “disable system configuration?” value; at that prompt, enter “Y” for yes and hit enter.

7. Reload the ASA by using entering:

rommon #2> boot

The ASA loads a default configuration instead of the startup configuration.

8. Enter privileged EXEC mode by entering:

hostname> en

9. When prompted for the password press “Enter” so the password will be blank.

10. Next Load the startup config by entering:

hostname# copy startup-config running-config

11. Enter global configuration mode by using this command:

hostname# config t

12. Change the passwords in the configuration by using these commands, as necessary:

hostname(config)# password newpassword
hostname(config)# enable password newpassword
hostname(config)# username newusername password newpassword

13. Change the configuration register to load the startup configuration at the next reload by entering:

hostname(config)# config-register 0x00000011

* Note- 0×00000011 is the current configurations register you noted in step 4.

13. Save the new passwords to the startup configuration by entering:

hostname(config)# wr mem


The commands used in the example above were referenced from Cisco article

Configuring a Cisco ASA 5505 with the basics

Thursday, March 1st, 2012

The Cisco ASA 5505 is great for small to medium businesses. Below are the steps you will have to complete to configure your ASA to communicate with the internet. There are many more steps, options, and features to these devices (which later there will be more articles in regards to some of these features).

Bring your device into configuration mode
Brings the device into enable mode

318ASA#config t
Change to configuration terminal mode

The ASA is now ready to be configured when you see (config)#

Configure the internal interface VLAN (ASA’s use VLAN’s for added security by default)
318ASA(config)# interface Vlan 1

Configure interface VLAN 1
318ASA(config-if)# nameif inside
Name the interface inside

318ASA(config-if)#security-level 100

Set’s the security level to 100

318ASA(config-if)#ip address
Assign your IP address

318ASA(config-if)#no shut
Make sure the interface is enabled and active

Configure the external interface VLAN (This is your WAN\internet connection)
318ASA(config)#interface Vlan 2
Creates the VLAN2 interface

318ASA(config-if)# nameif outside
Name’s the interface outside

318ASA(config-if)#security-level 0
Assigns the most strict security level to the outside interface (lower the number the higher the security).

318ASA(config-if)#ip address
Assign your Public Address to the outside interface

318ASA(config-if)#no shut
Enable the outside interface to be active.

Enable and assign the external WAN to Ethernet 0/0 using VLAN2
318ASA(config)#interface Ethernet0/0
Go to the Ethernet 0/0 interface settings

318ASA(config-if)#switchport access vlan 2
Assign the interface to use VLAN2

318ASA(config-if)#no shut
Enable the interface to be active.

Enable and assign the internal LAN interface Ethernet 0/1 (note ports 0/1-0/7 act as a switch but all interfaces are disabled by default).
318ASA(config)#interface Ethernet0/1
Go to the Ethernet 0/1 interface settings

318ASA(config-if)#no shut
Enable the interface to be active.
If you need multiple LAN ports you can do the same for Ethernet0/2 to 0/7.

To have traffic route from LAN to WAN you must configure Network Address Translation on the outside interface
318ASA(config)#global (outside) 1 interface
318ASA(config)#nat (inside) 1

***NOTE for ASA Version 8.3 and later***
Cisco announced the new Cisco ASA software version 8.3. This version introduces several important configuration changes, especially on the NAT/PAT mechanism. The “global” command is no longer supported. NAT (static and dynamic) and PAT are configured under network objects. The PAT configuration below is for ASA 8.3 and later:

318ASA(config)#nat (inside,outside) dynamic interface

For more info you can reference this article from Cisco with regards to the changes –

Configure the default route (for this example default gateway is
318ASA(config)#route outside 2 1

Last but not least verify and save your configurations. If you do not save your configurations you will have to.

Verify your settings are working. Once you have verified your configurations write to memory to save the configuration. If you do not write to memory your configurations will be lost upon the next reboot.

318ASA(config)#wr mem

Creating an Access List on a Cisco ASA

Tuesday, November 8th, 2011

Cisco provides basic traffic filtering capabilities with access control lists (also referred to as access lists). Access lists can be configured for all routed network protocols (IP, AppleTalk, and so on) to filter the packets of those protocols as the packets pass through a router. You can configure access lists on your ASA router to control access to a network: access lists can prevent certain traffic from entering or exiting a network. You can do this by port or IP address.

The access control list (ACL) methodology on the Cisco ASA is interface-based. Therefore, each interface must have a specified security level (0-100), with 100 being most secure and 0 being least secure. Once configurations are in place, traffic from a more secure interface is allowed to access less secure interfaces by default. Conversely, less secure interfaces are blocked from accessing more secure interfaces.

Some common commands used to configure Cisco ASA interfaces include:

  • nameif – used to name the interface
  • security-level – used to configure the interface’s security level
  • access-list – used to permit or deny traffic
  • access-group – applies an ACL to an interface

We can configure an access list to permit or deny traffic, based on a specific port or protocol. With deny-by-default, everything is automatically blocked and must be explicitly allowed (on Routers it is the opposite where everything is allowed and you have to deny ports or protocols to block them).

Let’s say we want to configure an ACL on an ASA to permit all FTP traffic from any host to To do this, we must input the following ACL:

ASA(config)# access-list OUTBOUND permit tcp any host eq ftp

Now let’s say we want to configure an ACL on an ASA to deny all FTP traffic from any host to To do this, we must input the following ACL:

ASA(config)# access-list OUTBOUND deny tcp any host eq ftp

Access lists are also used in defining rate limit’s when defining QOS settings. Here is a helpful guide to assist in choosing the right number to associate to an ACL:

Protocols with Access Lists Specified by Numbers

  • Protocol                                                                          Range
  • IP                                                                                      1-99, 1300-1999
  • Extended IP                                                                   100-199, 2000-2699
  • Ethernet type code                                                       200-299
  • Ethernet address                                                          700-799
  • Transparent bridging (protocol type)                    200-299
  • Transparent bridging (vendor code)                      700-799
  • Extended transparent bridging                               1100-1199
  • DECnet and extended DECnet                                 300-399
  • XNS                                                                                 400-499
  • Extended XNS                                                               500-599
  • AppleTalk                                                                      600-699
  • Source-route bridging (protocol type)                   200-299
  • Source-route bridging (vendor code)                     700-799
  • IPX                                                                                  800-899
  • Extended IPX                                                               900-999
  • IPX SAP                                                                        1000-1099
  • Standard VINES                                                           1-100
  • Extended VINES                                                          101-200
  • Simple VINES                                                               201-300

Disabling Spanning Tree on Cisco Switches

Monday, February 21st, 2011

Spanning Tree Protocol has always been a problem with Mac OS X Server. This goes back to the early days when OS’s whacked each other over the head with rocks to go from Alpha to Beta. This usually manifests itself in weird speed and connectivity issues. You can mitigate by changing timing values, but when testing, it is often easiest to start by disabling Spanning Tree Protocol, seeing if the problems you have go away and then working from there.

By default, Spanning Tree is enabled on all Cisco Switches. In this article we’ll look at disabling Spanning Tree Protocol. But it is important to point out that once disabled, it is important to keep in mind that creating an additional VLAN automatically runs another instance of spanning tree protocol, so you may need to repeat this process in the future.

First backup the device. Then, ssh into the device:

ssh admin@

You should be prompted for credentials at this time if using telnet. If you are using SSH you should only be prompted for the password. Once connected to the device you will need to go into enable mode by typing en at the command prompt and hit enter:


It may prompt you for a password, which you will need to know. Once complete you will notice that the prompt turns from an > to an # symbol. Now that you have administrative access, you will need to go into global configuration mode using the config t command:

config t

Now let’s actually disable spanning tree protocol. Enter in the no verb followed by spanning-tree, the protocol we’re disabling, followed by VLAN, followed by the VLAN identifier:

no spanning-tree VLAN vlan-id

Repeat for each VLAN if you need to do this on multiple. When done, exit config mode by entering the end command:


You can then enter the show command along with the spanning-tree option and view to see if there are any remaining spanning tree’s still active and verify if your command took:

show spanning-tree

If the command took and spanning tree is no longer enabled. Run the coppy command, followed by running-config and then startup-config, which copies your running configuration to your startup configuration making your change permanent:

copy running-config startup-config

It is then usually recommended to go ahead and reboot servers and clients prior to testing.

Backing Up Cisco Configurations Using Mac OS X

Friday, February 18th, 2011

Before you make configuration changes on devices you should make a backup of the device. You can basically use any platform you want to backup Cisco devices. Doing so in Mac OS X starts with the Terminal. So to backup a Cisco device you must first connect to the device in Terminal either through SSH or Telnet.

Then SSH to the device using the ssh command, followed by the username, an @ symbol and then the IP address or hostname of your device. Here, we’ll use an example of

ssh admin@

Note: One could also use telnet using the same type of string, but ssh is more secure.

Next, provide the password and you will see a prompt with the device name. Once connected to the device you will need to go into enable mode by typing “en” at the command prompt and hit enter. It may prompt you for an elevated privileges password, which you will need to know.

Once complete you will notice that the prompt turns from a > to a # symbol. The # symbol is akin to having root access. Now to backup the configuration of this device you will enter “show run” which is short for show running-config:

show run

You will see a ←-more→ prompt at the bottome of the page. Just hit the space bar until you are back a the prompt. Once you are at the prompt you will highlight all the text using your mouse that was just generated in the terminal and after its all highlighted hit “Command C” to copy the contents. Open your favorite text editor and use the “Command V” to paste the text. Be careful to use plain text here (I prefer to just use pico or vi rather than Word or TextEdit). Save the file as your configuration backup file for the Device.

NOTE: If you want to also get the IOS (IOS is different than iOS) version info you can run the “show version” instead of the “show run” command. And use the same steps to cut and paste.

If you cannot log into a device remotely, you can use a Keyspan adapter to use the serial port to connect to the device.

Mac OS X Server 10.5: NATd

Tuesday, August 12th, 2008

There are certain aspects of Mac OS X Server that it just isn’t that great at. One of them is acting as a router. It’s just a fact that an appliance by SonicWALL, Cisco, Watchguard and sometimes LinkSys will run circles around the speed and feature set of Mac OS X Server. So with that in mind, let’s look at how you would go about configuring a basic port forward on OS X Server if you decided not to listen to us on this point…

You can use the /etc/nat/natd.plist. The key you’ll want to edit is the redirect_port, one per port or a range of all in one key… Basically the array would look something like this assuming you were trying to forward afp traffic to from a WAN IP of










You could also use the route command or ipfw depending on exactly what you’re trying to do with this thing. Route is going to be useful if you’re trying to respond to network traffic over a different interface than the default interface.

Dual WANs for Your Office

Tuesday, September 5th, 2006

Often, a single internet connection is all that is needed to allow a group of computers to access the internet for websites, email and chatting. DSL, Cable Modem or a single T1 can often provide enough bandwidth for a small group of users.

As your company grows, there can come a point where the speed of the internet connection becomes a bottleneck, increasing the time for web pages to load and for emails to be sent and received. After you hit the limits of what a single connection is able to provide, one very cost effective way to address the issue is to add a second connection.

Adding a second internet connection to your network is also highly recommended if your business relies heavily on the internet. In the event of a downed internet connection, the outage could cost companies thousands of dollars in lost productivity and client interaction. By utilizing a second internet connection from an alternate provider, businesses can ensure a higher level of availability and uptime.

The equipment can be set up in one of two ways. When setup in a failover configuration, the second internet connection is used only when the primary fails. In typical configurations, the fast data connection such as a T1 is supplemented by the slower connection, such as DSL, to bear the burden of connectivity in the event of an outage.

When setup with load balancing, both internet connections are used simultaneously, with the traffic load being split and routed to the more ‘available’ connection. In this configuration, both data circuits should be sufficiently fast to allow the load to be effectively shared between both circuits, typically T1’s.

318 is an expert in setting up and integrating Dual-WAN networks. It can be as simple as using a DSL line and a cable modem, or as robust as using two T1s from two different providers. Or even an mix of a T1 and WiMax link. If you think this is a situation that would suit your business, give 318 a call to discuss your options.

Fear and Loathing Hackers in Los Vegas

Wednesday, September 14th, 2005

While attending DefCon, a hacking conference in Las Vegas, Three18 staff members learned of Ciscogate. Ciscogate revolves around the plight of Mike Lynn. He was a researcher for Internet Security Systems Inc (ISS) until he resigned last week after giving a speech at Black Hat, an Information Technology security conference in Las Vegas. Due to the presentation and the speech Lynn gave a suit was filed against him by ISS and Cisco.

Cisco hired people to go through the CDs given out by Black Hat containing all of the presentations and replace them with CDs absent the presentation. The first appearances of the case in the media were taken down, reportedly by Cisco. Cisco began to cover up the flaws Lynn exposed in their operating system, claiming that they were not as serious as Lynn had reported. In a bold move, Cisco also had Lynn slapped with a gag order and settled the case out of court with the stipulation that Lynn never talk of the vulnerabilities again.

The presentation exposes serious security vulnerabilities to the Cisco operating system. Theoretically it is possible to exploit this flaw in order to bring entire legs of the Internet dark. Due to the scale of the exploit and the anti-trust issues surrounding the case, the FBI and Justice Department are now investigating Lynn for criminal charges. If the flaws to Cisco’s operating system were not as serious as Lynn reported then why is the federal government involved?

We were amazed at the solidarity of the Hacker community around Lynn. A defense fund was started for him, copies of his speech were plastered across the Internet and shirts were printed overnight that read Ciscogate, the name given for the reported cover-up.

After returning home, Three18 worked hard at ensuring all of our clients’ routers were fully patched, which reportedly fixed the flaw Lynn uncovered. The point of Lynn’s disclosure of the seriousness of the vulnerabilities is to get System Administrators to patch their routers, which many of them might not have done otherwise.