FWSM Multiple-contexts Configuration

Answered Question
Jan 30th, 2009
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Dear NetPros;


Is there any limitation or precautions when implementing multiple-contexts plus shared VLAN with MSFC?


I'm currently using multiple-contexts with seperate VLANs with MSFC and my new FWSM will be configured with shared VLAN.


Any opinion would be appreciated.


Thanks,

Charles

Correct Answer by Syed Iftekhar Ahmed about 8 years 4 months ago


Multiple context mode does not support the following features:

• Most dynamic routing protocols. BGP stub mode is supported.

• Multicast routing. Multicast bridging is supported.


Now Shared interface


Problem with FWSM is that it has only one MAC address. When vlans are shared among multiple contexts the FWSM's "Classifer" selects the appropriate context on the basis of  Destination address of the traffic only. This requires setting up Static NAT rules on contexts to enable "classifier" to make decisions.


Since for Internet/outbond traffic you dont know all the destinations and cannot create NAT rules for all destinations, It is not possible to share inside interfaces of the contexts.


Sharing is also not possible and permitted between Transparent Contexts


Sharing Vlans needs to be avoided whereever possible with FWSM for simplicity Sake..


Syed iftekhar Ahmed


 

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Correct Answer
Syed Iftekhar Ahmed Fri, 01/30/2009 - 19:03
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Multiple context mode does not support the following features:

• Most dynamic routing protocols. BGP stub mode is supported.

• Multicast routing. Multicast bridging is supported.


Now Shared interface


Problem with FWSM is that it has only one MAC address. When vlans are shared among multiple contexts the FWSM's "Classifer" selects the appropriate context on the basis of  Destination address of the traffic only. This requires setting up Static NAT rules on contexts to enable "classifier" to make decisions.


Since for Internet/outbond traffic you dont know all the destinations and cannot create NAT rules for all destinations, It is not possible to share inside interfaces of the contexts.


Sharing is also not possible and permitted between Transparent Contexts


Sharing Vlans needs to be avoided whereever possible with FWSM for simplicity Sake..


Syed iftekhar Ahmed


 

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