I have encountered today a very strange situation: I connected a 7940 phone to my desk switch (it's a lousy Surecom switch, with no VLANs or other stuff) and that switch is connected to another switch - and from there, to the company's routing infrastructure (also to a CallManager). I mention that my laptop is connected to the same Surecom switch as the phone.
The weird thing is that after phone starts, it respons to ping from my laptop, and it responds to 3-4 ping packets sourced from a router (that lies somewhere in the company network, but has direct connection, through switches, with the phone). After those 3-4 replies, phone no longer replies to pings sourced from the router, but only replies to pings coming from my laptop. I put the phone in another ports on the switch - same happened. I connected the phone to the upstream switch - same happened.
I really don't understand why the phone stops replying to pings (this is also a sign that no other packets from phone to router or CM are passing through).
Has any of you encountered such a situation?