Clear Command on CISCO Router/Switch




This command is used to clear various counters in IOS as well as to reset various routing protocol adjacencies.


Router#clear <option>

Optional Switches

aaaClear AAA values
access-listClear access list statistical information
adjacencyAdjacent nodes
alpsClear Alps
appletalkReset AppleTalk information
arp-cacheClear the entire ARP cache
backhaul-session-manageBackhaul Session Manager information
bgpClear BGP connections
bridgeReset bridge forwarding cache
bscClear counters in command
bstunClear counters displayed in show bstun
cdpReset cdp information
cefCEF information related to linecard
cnsCNS agents
countersClear counters on one or all interfaces
cryptoEncryption subsystem
decnetReset DECnet information
dialerClear dialer statistics
dlswData Link Switching (DLSw)
dot1xClear Dot1x information
dripClear drip
dspfarmclear DSPFARM
frame-relayClear Frame Relay information
funiFUNI information
h323Clear H.323 protocol related information
hostDelete host table entries
interfaceClear the hardware logic on an interface
ipxReset Novell/IPX information
isisClear IS-IS data structures
kerberosClear Kerberos Values
lineReset a terminal line
loggingClear logging buffer
mac-address-tableMAC forwarding table
memoryMemory counters
mgcpclear Media Gateway Control Protocol
mplsReset MPLS statistical information
mpoaMPOA clear commands
mrcpClear MRCP statistics
nciaNative Client Interface Architecture (NCIA)
netbios-cacheClear the entire NetBIOS name cache
oerOptimized Exit Routing information
pagpPort channel information
parserClear parser data
pppClear ppp statistics
pppatmPPP over ATM
pppoePPP over Ethernet
radiusClears radius server information
rbscpRBSCP statistics/information
rif-cacheClear the entire RIF cache
route-mapClear Route Map statistical information
rpms-procClear RPMS Process Information
rudpv1Clear Rudpv1 information
sccpoldclear Skinny Client Control Protocol
scpClear SCP commands
sip-uaClear SIP User Agent Information
snapshotClear Snapshot timers
source-bridgeClear counters displayed in “show source-bridge”
sssSubscriber Service Switch Information
stunClear counters displayed in show stun
subscriptionClear Subscriptions
tag-switchingReset tag switching information
tarpReset tarp information
tcpClear TGREP counters/session
vlanClear vLAN statistical information
voiceClear Voice
vpdnClear a VPDN entity
vspVoice Streaming Processing information
vtpClear VTP items
webvpnWebVPN information
x25Clear X.25 circuits
xotClear an XOT (X.25-Over-TCP) VC


Since there is so many different clear options, we have added a clear section with some of the more useful clear commands for a CCNA candidate.

R2#clear ip ospf process
Reset ALL OSPF processes? [no]: y
*Mar 1 04:52:42.914: %OSPF-5-ADJCHG: Process 1, Nbr on FastEthernet1/0 from FULL to DOWN, Neighbor Down: Interface down or detached
*Mar 1 04:52:43.110: %OSPF-5-ADJCHG: Process 1, Nbr on FastEthernet1/0 from LOADING to FULL, Loading Done