ZyXEL Communications ZyWALL 300 User Manual

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Chapter 13 Routing Protocols
ZyWALL USG 300 User’s Guide
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RIP uses UDP port 520.
13.1.2  Authentication Types
Authentication is used to guarantee the integrity, but not the confidentiality, of routing 
updates. The transmitting router uses its key to encrypt the original message into a smaller 
message, and the smaller message is transmitted with the original message. The receiving 
router uses its key to encrypt the received message and then verifies that it matches the smaller 
message sent with it. If the received message is verified, then the receiving router accepts the 
updated routing information. The transmitting and receiving routers must have the same key. 
The ZyWALL supports three authentication methods for RIP and OSPF routing protocols:
• None - no authentication is used.
• Text – authentication using a plain text password, and the (unencrypted) password is sent 
over the network. This method is usually used temporarily to prevent network problems.
• MD5 – authentication using an MD5 password and authentication ID.
MD5 is an authentication method that produces a 128-bit checksum, called a message-digest, 
for each packet. It also includes an authentication ID, which can be set to any value between 1 
and 255. The ZyWALL only accepts packets if these conditions are satisfied.
• The packet’s authentication ID is the same as the authentication ID of the interface that 
received it.
• The packet’s message-digest is the same as the one the ZyWALL calculates using the 
MD5 password.
For RIP, authentication is not available in RIP version 1. In RIP version 2, you can only select 
one authentication type for all interfaces. For OSPF, the ZyWALL supports a default 
authentication type by area. If you want to use this default in an interface or virtual link, you 
set the associated Authentication Type field to Same as Area. As a result, you only have to 
update the authentication information for the area to update the authentication type used by 
these interfaces and virtual links. Alternatively, you can override the default in any interface or 
virtual link by selecting a specific authentication method. Please see the respective interface 
sections for more information.
13.2  RIP Screen
The RIP screen is used to specify the authentication method, and it is used to maintain the 
policies for redistribution.
To access this screen, login to the web configurator. When the main screen appears, click 
Network > Routing > RIP to open the following screen.