Implementing VPN Solutions Laurel Boyer, CCIE 4918 Presented, June 2003

Agenda  Cost Analysis: Frame vs. VPN  VPN Drawbacks  VPN Equipment Alternatives  Using GRE for Dynamic Routing  Implementation Examples  Troubleshooting  Questions/Discussion

Cost Analysis: Frame vs. VPN  Premise – This discussion assumes that there is a requirement to remotely connect two or more offices/locations. This discussion focuses on a Hub/Spoke architecture.  Frame Relay to DSL Cost examples

VPN Drawbacks  VPN connections traverse the Internet, resulting in vulnerabilities due to latency and interruptions that the network administer cannot influence.  DSL is normally a better choice than Cable Modem, as it does not share the broadcast media  DSL may not be available in all areas, or may not be available at the required speeds.  All DSL/ISP providers are not created equal. –Ensure that provider will give you public IP addresses to manage. –Ask provider where the POP is that connects to your office. –Request ping times from the POP to your Hub/Destination location. –Request peering information between provider and your destination. –Scrutinize customer service policy.

VPN Equipment Alternatives  PIX to PIX  PIX to VPN Concentrator  PIX to Router w/ IOS Firewall/IPSEC  VPN Concentrator to Router w/ IOS Firewall/IPSEC  VPN Concentrator to VPN Concentrator  Router w/ IOS Firewall/IPSEC to Router w/ IOS Firewall/IPSEC

VPN & GRE Example

Generic Steps for setting up VPN 1. Load Basic FW or Router Config 2. Set up IPSEC Tunnel 3. Set up static routes on Routers 4. Set up GRE Tunnel

Configure IPSEC Tunnel: ISAKMP 1. Define Encryption Algorithm: normally DES or 3DES 2. Define a Hashing Algorithm: MD5 or SHA 3. Define Authentication RSA/CA or Pre- shared Key 4. Define SA (Security Association) Lifetime. Default is (1 day)

Configure IPSEC Tunnel: ISAKMP Example: crypto isakmp policy 10 hash md5 authentication pre-share crypto isakmp key vpn2vpn address

Configure IPSEC Tunnel: IPSEC 1. Create extended ACL (Access List) 2. Create IPSEC transform(s) 3. Create Crypto Map 4. Apply Crypto Map to Interface

VPN Router Configuration crypto isakmp policy 10 hash md5 authentication pre-share crypto isakmp key vpn2vpn address ! crypto ipsec transform-set ESP-DES-MD5 esp-des esp-md5-hmac ! crypto map vpntunnel 10 ipsec-isakmp set peer set transform-set ESP-DES-MD5 match address vpn-tunnel ! interface Ethernet0 ip address ip nat inside !

VPN Router Configuration, Cont. interface Ethernet1 ip address ip nat outside crypto map vpntunnel ! ip nat inside source route-map Internet interface Ethernet1 overload ! ip access-list extended Nat deny ip permit ip any any ip access-list extended vpn-tunnel permit ip route-map Internet permit 10 match ip address Nat

VPN PIX Configuration nameif ethernet0 outside security0 nameif ethernet1 inside security100 access-list vpn-tunnel permit ip interface ethernet0 10baset interface ethernet1 10full ip address outside ip address inside nat (inside) 0 access-list vpn-tunnel nat (inside) route outside

VPN PIX Configuration, Cont. sysopt connection permit-ipsec crypto ipsec transform-set ESP-DES-MD5 esp-des esp-md5-hmac crypto map vpntunnel 1 ipsec-isakmp crypto map vpntunnel 1 match address vpn-tunnel crypto map vpntunnel 1 set peer crypto map vpntunnel 1 set transform-set ESP-DES-MD5 crypto map vpntunnel interface outside isakmp enable outside isakmp key vpn2vpn address netmask isakmp policy 1 authentication pre-share isakmp policy 1 encryption des isakmp policy 1 hash md5 isakmp policy 1 group 1 isakmp policy 1 lifetime 86400

VPN & GRE  GRE: Generic Routing Encapsulation. Used to encapsulate a wide variety of protocol packet types inside IP tunnels, creating a virtual point-to-point link to remote points over an IP network.  In this instance, we use an IPSEC tunnel to create a secure/encrypted path between to public points. GRE is used to create a virtual Intranet path between two private points.  Because GRE facilitates broadcast and multicast traffic, we can run EIGRP or other dynamic protocols, reducing the need for static routing in larger VPN topologies.

GRE Example interface Loopback10 description Loopback for GRE tunnel ip address ! interface Tunnel10 description GRE tunnel to GRE-RTR ip address tunnel source Loopback10 tunnel destination ! ip access-list extended vpn-tunnel permit ip host host ! ip route

Intro the VPN Concentrator Cisco VPN 3005 Cisco VPN 3015 Cisco VPN 3030 Cisco VPN 3060 Cisco VPN 3080 Simultaneous Users 100 1,5005,00010,000 Maximum LAN-to-LAN Sessions ,000 Encryption Throughput 4 Mbps 50 Mbps100 Mbps Encryption Method Software Hardware Available Expansion Slots Encryption (SEP) Module Redundant SEP Option Yes System Memory 3264 MB (fixed) 128 MB 128/256 MB 256/512 MB Client License Unlimited

TroubleshootingTroubleshooting, Cont.  Check IPSEC Tunnel –Show crypto ipsec sa –Show crypto isakmp sa –Clear crypto sa –Debug crypto ipsec –Debug crypto isakmp  Check for mismatched access-lists (most common problem!)  Check for static routes - you must tell the local router/FW that the private destination is via the public interface

Questions ?