Cisco RV016 - Small Business - 10/100 VPN Router Administration Manual page 137

VPN
Setting Up a Gateway to Gateway (Site to Site) VPN
Cisco Small Business RV0xx Series Routers Administration Guide
- AH Hash Algorithm: The AH (Authentication Header) protocol describes
the packet format and default standards for packet structure. With the
use of AH as the security protocol, protection is extended forward into
the IP header to verify the integrity of the entire packet. Check the box to
use this feature. Then select an authentication method: MD5 or SHA1.
MD5 produces a 128-bit digest to authenticate packet data. SHA1
produces a 160-bit digest to authenticate packet data. Both sides of the
tunnel should use the same algorithm.
- NetBIOS Broadcast: NetBIOS broadcast messages are used for name
resolution in Windows networking, to identify resources such as
computers, printers, and file servers. These messages are used by
some software applications and Windows features such as Network
Neighborhood. LAN broadcast traffic is typically not forwarded over a
VPN tunnel. However, you can check this box to allow NetBIOS
broadcasts from one end of the tunnel to be rebroadcast to the other
end.
- NAT Traversal: Network Address Translation (NAT) enables users with
private LAN addresses to access Internet resources by using a publicly
routable IP address as the source address. However, for inbound traffic,
the NAT gateway has no automatic method of translating the public IP
address to a particular destination on the private LAN. This issue
prevents successful IPsec exchanges. If your VPN router is behind a NAT
gateway, check this box to enable NAT traversal. Uncheck the box to
disable this feature. The same setting must be used on both ends of the
tunnel.
- Dead Peer Detection (DPD): Check the box to enable the router to send
periodic HELLO/ACK messages to check the status of the VPN tunnel.
This feature can be used only when it is enabled on both ends of the
VPN tunnel. Specify the interval between HELLO/ACK messages (how
often you want the messages to be sent).
Tunnel Backup: When DPD determines that the remote peer is
unavailable, this feature enables the router to re-establish the VPN tunnel
by using either an alternative IP address for the remote peer or an
alternative local WAN interface. Check the box to enable this feature.
Then enter the settings described below. This feature is available only if
Dead Peer Detection is enabled.
Remote Backup IP Address: Specify an alternative IP address for the
remote peer, or re-enter the WAN IP address that was already set for the
remote gateway.
9
137