- decnet is disabled
router#sh decnet 
% DECnet is not enabled

- transport input set to telnet
- ios is c3725-adventerprisek9-mz.124-25c.bin

BUT : 
router#sh int f0/0 counters protocol status 
Protocols allocated:
 FastEthernet0/0: Other, IP, DEC MOP, ARP, CDP, IPv6

http://blogs.cisco.com/security/router_spring_cleaning_-_no_mop_required/
http://www.cisco.com/en/US/tech/tk870/tk136/tk885/technologies_tech_note09186a0080093cd1.shtml

solution :
interface FastEthernet0/0
 no mop enabled

router#sh run int f0/0 | i mop
 no mop enabled

router#sh int f0/0 count prot status 
Protocols allocated:
 FastEthernet0/0: Other, IP, DEC MOP, ARP, CDP, IPv6