Subnetting an ISP block with Gbe2c

[Jason Biggin]

I have deployed a c-class chassis in a co-lo that is equipped with a Gbe2c 2/3 internal switch.

The ISP has provided a block of 8 addresses, netmask 255.255.255.248, and I want to subnet this into two.

All is configured with an external vlan and an internal vlan configured with address subnetted with 255.255.255.252.

From the Gbe2c i am able to ping the ISP interface, both attached interfaces and the single internal server interface.

From the internal server i am able to ping the internal vlan interface (it's gateway) and external vlan interface, but not the ISP interface.

The default (and only) route on the Gbe2c is the ISP interface, and I am able to ping external addresses.

What am i missing?

Thanks!

[Jason Biggin]

One thing i believe is that the Gbe2c needs to do is summarize the the net mask to the ISP.

Any thoughts are greatly appreciated.