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Step-by-Step Configuration and Troubleshooting Best Practices for the NGFW, NGIPS and AMP Technologies A Visual Guide to the Cisco Firepower Threat Defense (FTD)
New Member

PIX Interface Speed

I have a PIX 525 that connects to a 6508 switch. The switch port is configured to auto and the PIX is 100 full. I trying to connect packet filter box in between. If I change the port configuration on the 6509 to 100 full, traffic drops. If I put it back to auto, traffic comes back. I read that it was not recommended to configure the PIX to auto. Any ideas why the traffic would drop?


Re: PIX Interface Speed

check this bug-id:CSCei57980

If you have made trunk port, refer this note:

When configuring VLANs on a PIX, ensure that the physical interface is not assigned the same VLAN ID as the native VLAN on the other end of the trunk. This way, traffic from the PIX does not forward to the native VLAN on the switch. This prevents vulnerability to the jumping VLAN attack.

New Member

Re: PIX Interface Speed

Its not recommended to set ANY port to 'auto.'


Re: PIX Interface Speed

what sort of packet filter box are you trying to connect? how are the interfaces on this box configured?

when using auto negotiate, 10/100 interfaces default to 100half if other side is hard coded at anything (including 100full) since there will be no negotiation signaling coming from the 100full side.

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