DsmbISP_Final_Exam_-_CCNA

DsmbISP_Final_Exam_-_CCNA
ICO compares TalkTalk anti-malware technology to Phorm
Enterprise risk management: Get started in six steps
Return of the Spam Heckler
ACLU, other groups sue US gov't over border laptop searches
Microsoft investigates two-year-old IE bug
Basic Cisco 800 Router Configuration for Internet Access

Posted: 07 Sep 2010 06:05 PM PDT

New =>DsmbISP_Final_Exam_-_CCNA

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ICO compares TalkTalk anti-malware technology to Phorm

Posted: 07 Sep 2010 09:00 AM PDT

The Information Commissioner's Office has compared TalkTalk's new anti-malware technology to controversial targettered advertising firm Phorm.

Enterprise risk management: Get started in six steps

Posted: 07 Sep 2010 09:00 AM PDT

Let's say your organization doesn't have a formal enterprise risk management program. If you're at a big company, ERM might seem daunting because of silos, inertia and so on.

Return of the Spam Heckler

Posted: 07 Sep 2010 09:00 AM PDT

About a year ago, I wrote an article for this site that began by praising the craft required to produce a spam header intriguing enough to coax an innocent recipient into opening the unsolicited message (see "Straight to the Spam Folder: Astonishing E-Mail Messages You'll Never Open"). Then I spent the rest of the story mocking various spam headers that editors at PCWorld had recently received.

ACLU, other groups sue US gov't over border laptop searches

Posted: 07 Sep 2010 09:00 AM PDT

The American Civil Liberties Union and other groups have filed a lawsuit challenging the U.S. Customs and Border Protection (CBP) practice of searching laptops and other electronic devices at U.S. borders.

Microsoft investigates two-year-old IE bug

Posted: 07 Sep 2010 09:00 AM PDT

Microsoft is looking into a long-known vulnerability in Internet Explorer (IE) that could be used to access users' data and Web-based accounts.

Basic Cisco 800 Router Configuration for Internet Access

Posted: 07 Sep 2010 01:13 AM PDT

The Cisco 800 series routers are part of the "Branch Office" category, used mainly for SOHO purposes or for connecting remote branch offices to a central location. They are "fixed hardware configuration" devices, meaning that they don't have any plug-in hardware slots for inserting additional interfaces to the device (all the interfaces are fixed).

All the 800 series models come with a 4-port 10/100 managed switch used for connecting the internal LAN computers, and with an IOS software that supports security features including the Firewall set. The main difference of each model is the WAN interface. All models that end with "1" in the model number (i.e 851, 861, 871, 881, 891) have a 10/100 Fast Ethernet interface as a WAN port. The other models have an xDSL type WAN port (i.e ADSL, G.SHDL, VDSL2). Also, all models have the option of a WiFi Radio interface (the model number ends with a "W", e.g 851W, 857W, 861W etc).

In this post I will describe a basic configuration scenario for connecting a Cisco 800 router for Internet access. I will use a model with an Ethernet WAN interface (such as 851, 861, 871, etc) since those models are the most popular.

Something to have in mind for all 800 series routers, the four LAN interfaces (FE0 up to FE3) are Layer2 switch interfaces that are assigned by default to Vlan1. This means that you can not assign an IP address directly to the LAN interfaces. The IP address for the LAN-facing side of the router is assigned under "interface Vlan1". On the other hand, the WAN interface (FE4) is a normal Layer3 router port, which means you can assign an IP address directly on the interface ("interface FastEthernet4").

I will describe three basic scenarios which are frequently encountered in real networks.

Scenario 1: WAN IP address of router is assigned dynamically by the ISP. LAN IP addresses assigned dynamically from the router to the internal PCs.
Scenario 2: WAN IP address of router is static. LAN IP addresses assigned dynamically from the router.
Scenario 3: WAN IP address of router is static. An internal LAN Web Server exists. The router performs a static Port NAT (port redirection) to forward traffic from Internet towards the internal Web Server.

Scenario 1:

Configuration:

The following is the basic configuration needed for the simple scenario above.

configure terminal

enable secret somesecretpassword

! Configure the DHCP pool to assign addresses to internal hosts
ip dhcp pool vlan1pool
   network 192.168.1.0 255.255.255.0
   default-router 192.168.1.1
   dns-server 100.100.100.36

! Do not assign addresses 1 to 30
ip dhcp excluded-address 192.168.1.1 192.168.1.30

! This is the LAN facing interface of the 800 router. Used as gateway for PCs
interface vlan 1
ip address 192.168.1.1 255.255.255.0
ip nat inside
no shut

! Interfaces FE0 to FE3 are Layer 2 interfaces
interface FastEthernet0
no shut
interface FastEthernet1
no shut

interface FastEthernet2
no shut

interface FastEthernet3
no shut

! This is the WAN interface getting address via DHCP from the ISP
interface FastEthernet 4
no shut
ip address dhcp
ip nat outside

! Configure NAT. All internal hosts will be nated on the WAN interface
ip nat inside source list 1 interface fastethernet4 overload
access-list 1 permit 192.168.1.0 255.255.255.0

ip route 0.0.0.0 0.0.0.0 fastethernet4

line vty 0 4
password somestrongpassword

Scenario 2:

Configuration:

This is the same configuration as scenario 1 except that the WAN IP address is static and also the default gateway of our ISP is known.

The only difference from the configuration above is on the WAN interface and on default route:

! This is the WAN interface with static IP

interface FastEthernet 4
no shut
ip address 100.100.100.1 255.255.255.0
ip nat outside

ip route 0.0.0.0 0.0.0.0 100.100.100.2

Scenario 3:

Configuration:

Here the WAN address is static and we have also an internal Web Server for which we need to allow HTTP access from Internet. To do this we must configure a static NAT with port redirection. Traffic that comes towards our WAN public address 100.100.100.1 on port 80 will be redirected by the router to the internal Web Server at address 192.168.1.10 on port 80.

configure terminal

enable secret somesecretpassword

! Do not assign addresses 1 to 30
ip dhcp excluded-address 192.168.1.1 192.168.1.30

! This is the LAN facing interface of the 800 router. Used as gateway for PCs
interface vlan 1
ip address 192.168.1.1 255.255.255.0
ip nat inside
no shut

! Interfaces FE0 to FE3 are Layer 2 interfaces
interface FastEthernet0
no shut

interface FastEthernet1
no shut

interface FastEthernet2
no shut

interface FastEthernet3
no shut

! This is the WAN interface with static IP
interface FastEthernet 4
no shut
ip address 100.100.100.1 255.255.255.0
ip nat outside

! Configure NAT. All internal hosts will be nated on the WAN interface
ip nat inside source list 1 interface fastethernet4 overload
access-list 1 permit 192.168.1.0 255.255.255.0

! Configure static NAT for port redirection
ip nat inside source static tcp 192.168.1.10 80 100.100.100.1 80 extendable

ip route 0.0.0.0 0.0.0.0 100.100.100.2

line vty 0 4
password somestrongpassword