3Com AccessBuilder 500 User Manual - page 52

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Enter 

SAVE

 at the command prompt to permanently store this 

configuration in the unit’s memory.

Although calls to the remote site are only generated when data is 

addressed to a specific IP host or hosts (in our example, 191.000.000.100), 

any data that cannot be identified as local is also passed over the link 

while it is open. This can prevent the link from closing after the intended 

data has been transferred.

To avoid this situation you can also configure the units at both ends of 

the link to implement a Firewall and/or set the

 Maximum Call Duration

 in 

the ISDN parameters screen to reduce the amount of traffic permitted to 

pass across the link. See the 

AccessBuilder ISDN Access Router Software 

Reference

 guide for more information about these features.

Alternatively, you may wish to configure the unit to operate as a router 

to prevent this problem occurring altogether. However, this requires 

that each site consists of separate subnets. See the next section for 

more information.