Group ProjectGroup ProjectProxy ServerProxy Server

CIS 454 LOCAL AREA NETWORKCIS 454 LOCAL AREA NETWORKPROFESSOR: DR. GANESANPROFESSOR: DR. GANESAN

GROUP #1GROUP #1ROBERT WANG, DI LY, LINDA WUROBERT WANG, DI LY, LINDA WUKAY AYARJOKEKAY AYARJOKE

Microsoft Microsoft Proxy Server Proxy Server

2.02.0

Course Outline

• Overview of Microsoft Proxy Server.

• Examples of Capacity Planning.• Web Proxy Server Configuration.• Proxy Server Auto Dial.

Overview of Microsoft Overview of Microsoft Proxy ServerProxy Server

Overview of Microsoft Proxy Server

• What is Proxy Server?• Firewall Server.• Web Cache Server.• 3 Proxy Services – Web Proxy,

WinSock Proxy, and SOCKS Proxy.• System Requirements.

What is Proxy Server ?

• A secure gateway between a protected network (LAN) and the Internet.

• Mediates traffic and processes all incoming and outgoing requests.

• Application server that acts as both a firewall server and a web cache server.

• Only One IP address is “visible” to outside world.

Proxy Server ExampleProxy Server Example

LANInternet

FTPGopherHTTP

Win NT

IIS

Proxy

Traffic

LAN

One IP address is visible.

IP addresses are hidden.

What is a Firewall ?What is a Firewall ?• System that enforces an access

control policy between two networks.• Some block traffic; others permit

traffic.• Protects against unauthenticated

logins from the “outside.”• A “phone tap” and tracing tool.• Cannot protect against attacks

outside of the firewall and viruses.

Types of FirewallsTypes of Firewalls

• Network Level (Router).– Decisions based on source, destination

addresses and ports in IP packets.– Route traffic directly, fast and transparent.

• Application Level (Proxy Server)– Permit no direct traffic between networks.– Good for logging and access control.– Provide detailed audit report.– Enforce more conservative security.

MS Proxy Server as MS Proxy Server as Firewall ServerFirewall Server

• Packet Filtering – examines all TCP/IP based attempts in & out of the network.– Static and Dynamic.

• Logs all connection attempts & alerts in real-time of the suspicious activities.

• Reverse Proxy - Places the web server behind Proxy Server to publish to the Web.– “Impersonates" a Web server to the outside.– Reverse Hosting & Server Proxying.

Reverse Proxy ExampleReverse Proxy Example

Proxy

Web Server

InternetClientMkt Dept

LAN

Secure Network

www.company.com

www.company.com

www.company.com

MS Proxy Server as Web MS Proxy Server as Web Cache ServerCache Server

• Web Caching – process of storing Web content locally to reduce network traffic.– Active and Passive.

• Allow internal clients to have full Web access behind the firewall without compromising security.

• Hierarchical Caching.• Distributed Caching.

Cache ExampleCache Example

Internet

1st client 2nd client

Connection to Internet

ProxyContentCached

50% Traffic Saving

Cache Hit!

Hierarchical Caching Hierarchical Caching ExampleExample

InternetProxy

ProxyProxy

New York

Los AngelesBoston

Client Client Client Client

Source: http://www.microsoft.com/proxy/guide/WebCach.asp?A=2&B=2

Distributed Caching Distributed Caching ExampleExample

Internet Proxy

1 Proxy

3 Proxy

4Proxy

2

Load BalancingFault toleranceScalability

Client Client Client Client Client Client

Source: http://www.microsoft.com/proxy/guide/WebCach.asp?A=2&B=2

WinSock, SOCKS, Web WinSock, SOCKS, Web ProxyProxy

• Protocols allow the application clients to communicate to application servers.

• Performs three functions: – Intercepts connection requests.– Sets up proxy circuit.– Relays application data.

WinSock & SOCKS Proxy• WinSock Proxy.

– For Window application.– Creating virtual connection between internal

and Internet application.– Acts as gateway protocol for IPX/SPX.

• SOCKS Proxy.– Allows Unix, Mac and Window client

application that support SOCKS protocol specification.

– Handles all TCP/IP traffic through the proxy server.

– Cannot Handle UDP based protocols.

Web ProxyWeb Proxy

• Web Proxy– Supports any CERN web browser.– Supports HTTP, FTP, SSL and Gopher

protocol.– Enables its caching capabilities.

System RequirementsSystem Requirements

• WinNT Server 4.0 with service pack 3 or later.

• IIS – Internet Information Server.• Network interface card.• CPU and disk space:

– Intel based: 486/33MHz or higher & 125MB.– RISC based: RISC processor compatible

with WinNT 4.0 & 160MB.

• 16MB of RAM.

Examples of Capacity Examples of Capacity ImplementationImplementation

Examples of Capacity Examples of Capacity PlanningPlanning

• Small Office Network.• Medium-Size Office Network with a

Branch Office.• Large Enterprise Network.

Example of Small Office Example of Small Office NetworkNetwork

Modem or ISDN line

ISP

Proxy Server(Win NT RAS client)

Web Server Mail Server

Internet

Client Client Client

ContentCached

LAN

Source: http://www.microsoft.com/proxy/guide/NetScenarios.asp?A=2&B=5

Small Office NetworkSmall Office Network• Characteristic:

– A single LAN segment.– Use of the IP network protocol.– Demand-dial connectivity to an ISP.– Fewer than 300 clients.

• The proxy-based computers set up:– One NIC to the internal network.– One modem to the external network (Internet).

• Uses Auto Dial for demand-dialing to Internet.

• Caching is enabled and configured to limit the demand-dialing to the Internet.

Small Office Network Small Office Network Cont . . . Cont . . .

• Stores a local copy of popular URLs in dedicated disk drive.

• Uses a single network security policy.– Password authentication.– User permissions.– Protocol definitions. – Domain, cache and packet filtering.

Example of Branch Office Example of Branch Office NetworkNetwork

Internet

ISP

ProxyServerArrayWeb Server Mail Server

Router

Web Server

(Department LAN)

Modem or ISDN Line

Web Server

Remote Branch Office

Proxy server(Win NT RAS client)

Router on T1 line

Clients

LAN

Clients

Source: http://www.microsoft.com/proxy/guide/NetScenarios.asp?A=2&B=5

Branch Office NetworkBranch Office Network

• Characteristic . . .– A central office with several LAN segments.– A branch office with a single LAN segment.– Use of the IP network protocol.– Demand-dial connectivity from the branch office

to the central office.– Dedicated-link connectivity from the central

office to an ISP.– Fewer than 2,000 clients.

• Auto Dial feature provides demand-dialing from remote office to central office.

Branch Office Network Cont . . .

• Proxy-based computer set up at branch:– One NIC to the local network (branch).– One modem to remote network at the central

office.

• Caching is enabled to minimize demand-dialing to central office and to reduce long-distance phone charge.

• Active caching should not be used at remote branch.

Branch Office NetworkBranch Office NetworkCont . . .Cont . . .

• Global Security policy:– Administrated at central office.– Central office can also set and override local

policy.

• Remote branch proxy has no direct Internet access.

• All clients requests are routed upstream to the proxy array at central office.

Example of Large Enterprise Example of Large Enterprise NetworkNetwork

InternetProxy ServerArray

Proxy ServerArray

RouterWeb Server

Department LAN

Web ServerMail Server

RouterWeb Server

Department LAN

ISP

CorporateNetwork

ClientsClients

Router on T1 line

Router

LAN

Source: http://www.microsoft.com/proxy/guide/NetScenarios.asp?A=2&B=5

Large Enterprise Network

• Characteristic . . .– A central corporate office with many LAN

segments and a backbone LAN.– Several branch offices, each with a single

LAN segment– Use of both IP and IPX network protocols.– Demand-dial connectivity from the branch

office to the central office.– An ISP & Dedicated-link connectivity from

the central office to an ISP.– More than 2,000 clients.

Large Enterprise Network Large Enterprise Network Cont . . .Cont . . .

• Proxy array is used for:– Distributed caching.– Load balancing.– Fault tolerance.

• Proxy array handles all client Internet requests (locally or branch).

• Active caching to retrieve popular URLs.

Large Enterprise Network Large Enterprise Network Cont . . .Cont . . .

• Uses single array member to administration all other proxy.

• Proxy array is used on the backbone LAN.• Is used at ISP to demonstrate scalability.• Local branch clients use Auto Dial for demand-

dialing to RAS server.• Internet requests not serviced locally are

forwarded to corporate proxy array.• Server administration is set and enforced at the

central office.

Large Enterprise Network Large Enterprise Network Cont . . .Cont . . .

• Departmental proxy connection:– One NIC to departmental LAN.– One NIC to backbone LAN.

• Proxy array at backbone is dual-homed.– Internal NIC.– External NIC to Internet.

• Proxy array at ISP:– Massive scalability, load-balancing, and fault-

tolerance.– Can cache massive amount of information.– Increases client performance.– Preserves ISP’s bandwidth out to the Internet

backbone.

Web Proxy Server Configuration

Proxy server configurationProxy server configuration

• Uses Internet Service Manager.• General Proxy.

– Service page.– Logging page.

• Service Specific Proxy.– Permission page.– Caching page.– Routing page.– Publishing page.

Service Page Notes

• Product release and ID.• Current sessions – current user info.• Shared service:

– Security – packet, domain filtering, alerting and logging.

– Array, Auto Dial, and Plug & play.• Configuration:

– Client configuration, LAT, server backup and restore.

Service PageService Page

Source: http://www.calstatela.edu/ats/cbt/

Current SessionsCurrent Sessions

Source: http://www.calstatela.edu/ats/cbt/

Client Installation

Source: http://www.calstatela.edu/ats/cbt/

Logging Page Notes

• Sets logging options for web proxy, WinSock proxy, and SOCKS proxy.

• Provides auditing trail.• Records client, server, connection,

and object information.• Can log to text file or SQL/ODBC

database.– Database file requires more resources.

Logging PageLogging Page

Source: http://www.calstatela.edu/ats/cbt/

Permissions Page NotesPermissions Page Notes

• Grant or deny access to services.• Can provide unlimited access to an

individual user group.• Permission based on protocol via

protocol definition.– For example:

• FTP.• FTP Read.

Permission PagePermission Page

Source: http://www.calstatela.edu/ats/cbt/

Caching Page NotesCaching Page Notes

• Sets location and size of the disk cache.

• Enable or disable caching.• Can specify how often to update

cache.• Increase cache size does not effect

the data already cached.• Delete all cached content by setting

cache size to zero.

Caching PageCaching Page

Source: http://www.calstatela.edu/ats/cbt/

Routing Page NotesRouting Page Notes

• Information on directing client requests for Internet objects.

• Direct connection or use proxy.• Can enable backup route.• Can enable routing within proxy

array before routing upstream.• Can also configure web proxy

clients.

Routing PageRouting Page

Source: http://www.calstatela.edu/ats/cbt/

Publishing Page Notes

• Configures publishing requests.• Configures Reverse proxy and

hosting.• Incoming requests:

– Discard.– Sent to local web server.– Sent to another web server.

• Set default web server host by Default Mapping.

Publishing PagePublishing Page

Source: http://www.calstatela.edu/ats/cbt/

Proxy Server AutoDialProxy Server AutoDial

What is AutoDial?What is AutoDial?

• Proxy server automatically dial out to an ISP for Internet connection.

• Uses Windows NT Server Remote Access Service (RAS) and Dial up Networking to establish a connection to an ISP.

• Event-driven– Client requests can activate Auto Dial from

the WinSock and SOCKS Proxy Service.– Web Proxy Service is activated when an

object requested is not located in the cache.

Auto Dial BenefitsAuto Dial Benefits

• Can save company Internet charges– Event-Driven - activated only when Internet

connection is needed.– Regulate Usage - configured to connect to the

Internet during office hours only.

• Can be used as backup to an existing continuous Internet links. – only cost of configuring Auto Dial as continuous

Internet connection are the hardware & the online time when a continuous Internet link is down.

Steps to Configuring Auto Steps to Configuring Auto DialDial

• Window NT Server Remote Access Service (RAS) and Dial-up Network before implementing Proxy Server Auto Dial.– For security reasons, install RAS Server on

separate computer of the Proxy Server computer.

• RAS and Dial-up Networking can be installed after or before the installation of Window NT Server 4.0.

Remote Access Service

• Remote Access Service can be configured in Auto Dial as an:– RAS Client - to dial out only.– RAS Server - can be both dial out

and receive calls or just receive calls only.

– RAS Server requires a high level of security on you Intranet.

Dial-up NetworkingDial-up Networking

• Used to connect client to remote networks.

• A phonebook entry stores all the setting needed to connect to a particular remote network.– Personal phonebook. – Company phonebook (public use).

Phonebook Entry IncludesPhonebook Entry Includes

• Name of phonebook entry.• Connection method.• Phone number.• Serial line protocol offered by the server

you are calling.• Whether or not to include a login script• IP address.• IP address of a DNS or WIN Server on

the remote network or both.

Netscape Netscape Proxy Server Proxy Server

3.253.25

Course OutlineCourse Outline

• General Overview.• Implementation.• Architecture.• Configuration.• Upgrade.

General OverviewGeneral Overview

FeaturesFeatures

• Caching on command.• Client IP address forwarding.• Automatic content discovery

– Dynamic proxy routing.

• Enterprise Management.• Fine Grained Filtering.• Administrative Control.

Caching on CommandCaching on Command

• Automatically update and caches frequently accessed documents.

• Documents or entire sites can be preloaded into the cache, and administrators can schedule updates of cached content.

Client IP Address Client IP Address ForwardingForwarding

• Sends clients IP address to remote server if the Proxy is one of a chain of internal proxies.

Enterprise ManagementEnterprise Management

• Centralize Management. – Support LDAP.– Uses Directory Server to manage

users and password centrally.

• Clustered Management.• Manual Configuration Files.• Custom log formats.

Fine Grained FilteringFine Grained Filtering

• Access controls for sites, documents, and protocols.

• Content filtering - built-in virus scanning.

• Cross - platform generic protocol support.

Administrative ControlAdministrative Control

• Ensures that users access network resources safely and productively.

• Can specify distinct access controls based on access type.

• Allows administrators to create custom HTML files to be returned to users when access is denied.

ImplementationImplementation

Netscape Proxy Server Netscape Proxy Server ImplementationImplementation

• Bottleneck locations for implementing Proxy Server.– Internet Gateway—Forward Proxy.– Branch Office—Forward Proxy.– Internet Gateway—Reverse Proxy.

Internet Gateway - Forward Internet Gateway - Forward ProxyProxy

• Provides gateway services at the application level with a web proxy as well as at the circuit level through SOCKS.

• Enhances Internet access. • Web content caching reduces response

times.• Facilitates bandwidth conservation.• Helps reduce overall communications

expense.• Content filtering and access control allows

easy management of intranet material.

Proxy Server inside Proxy Server inside firewallfirewall

Internet

Proxy LAN

PC

PC

PC

Firewall

Branch Office—Forward Branch Office—Forward ProxyProxy

• Multiple proxy server allows chaining proxies together to create a hierarchical caching system

• Proxy chaining allows multiple Netscape Proxy Servers to cache content locally setting up a hierarchy of servers for client access.

Proxy Server at Remote & Proxy Server at Remote & InternetInternet

Internet

Proxy

Firewall

Backbone

Proxy

LAN PC

Internet Gateway—Internet Gateway—Reverse ProxyReverse Proxy

• Proxy Server is placed outside firewall to represent a content server to external clients.

• Expose selected content without exposing web servers that host it or other elements of private network.

• Multiple reverse proxy servers can be used to balance the load on an over-taxed web server.

Reverse Proxy Server Reverse Proxy Server

Internet

ReverseProxy

Web Server LAN

PC

PC

PCFirewall

ArchitectureArchitecture

ArchitectureArchitecture

– Dual-Homed Host Architecture

– Screened Host

– Screened Subnetwork

– Reverse Proxy

– Server Stand-in

– Load Balancing

Dual-Homed Host Dual-Homed Host ArchitectureArchitecture

• Has two network interfaces, one connected to an internal LAN and the other to the Internet.

• Incorporates a firewall software package.

• Provides caching, fine-grain filtering and virus scanning.

Proxy Server with a Dual-Homed Proxy Server with a Dual-Homed Host FirewallHost Firewall

Internet

Proxy Server & Firewall

LAN

Client

Client

Screened Host

• Consists of a router deployed in front of a server that is hosted on a private network.

• Router can be traditional hardware router or firewall software application providing packet-filtering capabilities and restricting inbound access to internal network.

• Appropriate for small to medium-sized intranets that require a simple, yet effective security solution.

Proxy Server implemented behind a screening router

Internet

Router

Proxy Server

LAN

Client

Client

Proxy Server Implemented Behind a Screening Firewall

Internet

Firewall Software Router

Proxy Server

LAN

Client

Client

Screened Sub-network

• Consists of multiple routers sandwiching a non-secure network that is outside or part of the firewall solution.

• Commonly referred to as a DMZ (demilitarized zone). Proxy is deployed in DMZ and is allowed access to both internal and external networks through routers.

• Popular architecture choice for larger organizations with heavily trafficked gateways.

Proxy Server in Reverse Mode as a Stand-in for a Web Server

Client

Internet

Firewall Enterprise Server

Proxy Server

Multiple Proxy Server in Reverse Mode to Balance the Load on a Web

Server

Internet

FirewallEnterprise ServerReverse

Proxies

DNS Server

Chained Proxy Servers Providing Load Balancing and Fail-Over

Capabilities

Internet

Proxies

LAN

Router Router

LAN

Client

Client

Client

Client

Proxy A

Proxy 1

Proxy 2

Proxy 3

Possible enterprise implementation

Internet Router

Central Office

Subnet

Proxy Server

Router

LAN

Client

Client

Router Router Proxy Server

LAN

Client

Client

BRANCH OFFICE

Bottlenecks

ConfigurationConfiguration

ConfigurationConfiguration

• Automatic Client Configuration.• Caching.• Templates.• Filtering.• Server Plug-in Functions.

Automatic Client Configuration

• Enables automatic proxy configuration in Navigator clients on intranet.

• Administered by a Proxy Automatic Configuration (PAC) file.

• PAC allows load balancing across multiple proxy servers and alteration of proxy architecture without modifying end user settings.

Caching

• Caches should be approximately 1 GB per partition and spread across multiple disk controllers.

• Refer to Administrator’s Guide for in-depth instructions on creating batch update configurations.

TemplatesTemplates

• An object created in Proxy Server’s object configuration file, obj.conf.

• Used to assign unique procedures to specific URLs.

• Can make the server behave differently depending on the URL the client tries to retrieve.

• Allows customization of how Proxy Server interacts with clients.

Server Plug-in FunctionsServer Plug-in Functions

• Extends capabilities of proxy by using Netscape Server Plug-in Application Programming Interface, NSAPI.

• Set of functions and header files use to create functions in the server configuration files.– AuthTrans, PathCheck, NameTrans,DNS,

Connect, Addlog.

• Use to create functions that uses a custom database for access control or create custom log files with special entries.

Maintenance/UpgradeMaintenance/Upgrade

• Maintenance– Tuning the Servers– Monitoring the Servers

• Upgrade– Growth Issues– Licenses– Software Updates

Tuning Servers

• Time-outs.• Up-To-Date Checks.• DNS Lookups:

– Enable DNS Caching.– Log Only Client IP Addresses.– Disable Reverse DNS.– Avoid ACLs with Client Host Names.

• HTTP Keep-Alive.

Monitoring ServersMonitoring Servers

• Analyzing Logs.• Monitoring Performance:

– Cache Utilization.– CPU Utilization.– Memory Utilization.

UpgradeUpgrade

Upgrade

• Growth Issues– Is proxy services strategic for business?– Network bandwidth saturated?– CPU utilization too high?– Has a new field office been opened or

a department added– Has access content type been

changed?

Upgrade Cont . . .Upgrade Cont . . .

• LicensesProxy User Licenses Proxy Servers

Purchased Deployed

1000 1 2000 2 3000 3 4000 4

Upgrade Cont . . .Upgrade Cont . . .

• Software Updates– Refer to the Netscape Software

Download Site.– Netscape Proxy Server provides on-

the-fly virus scanning of all incoming data, using the Trend Micro’s InterScan VirusWall Purchase of Proxy Server give you 90 days of free virus pattern updates.

References

• www.microsoft.com• www.netscape.com• www.clarknet.com• www.whatis.com• www.calstatela.edu/ats/cbt/

(CBT)

END OF COURSE END OF COURSE