Clear arp-cache to ping

I have an SMS server on my network that is unreachable from vlans other that its own. This happened after we pushed out tumbleweed via SMS. Now, in order to ping the server I must issue a clear arp-cache in the core switch, this only last for about 1 min and then the SMS server is unreachable again. Any help would be great.

Thanks Dabels,
I have had this problem as well, it turned out to be a pix.
Proxy-arp is enabled by default on all interfaces and its not apparent in the config when its on or off. Its configured as a sysopt and therefore, it often gets overlooked.
Agree with everything you say, check the mac in the arp table of the server when your pings are failing, then trace the MAC you find there which corresponds to the ip address of the router.
Or check the arp entry in the router (again when its failing) and verify the MAC is the SMS server, it may just turn out to be a router or a pix or even....another server which is routing between a pair of NIC's, such as a unix box or a windows server.
Let us know how you get on.
Cheers
Shaun

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