Introduction
Here are some commands in cisco systems’ Internetworking Operating System
which are hidden from users at any privilege level. Some are informative,
while others are rather mundane. Some will even lock the router if invoked
incorrectly. This list is a subset of all hidden commands. Descriptions
of commands are included where possible. All were tested on a box running
12.0-6S.
exec commands
@clear profile (clear cpu profiling)
@debug ip ospf monitor
@debug oir (debug online insertion and removal)
@debug par mo (debug parser modes)
@debug sanity (debug buffer pool sanity)
@debug subsys (debug discrete subsystems)
@debug buffer (additional buffer debugging)
@gdb kernel
@gdb examine pid
@gdb debug pid
@if-console [<slot>] [console|debug]
@profile <start> <stop> <granularity>.
@sh chunk (show chunks of memory allocated to processes)
@sh chunk summ (show chunk allocation summary)
@sh idb (shows interface database)
@sh in stats (gives you switching path output per interface)
@sh ip ospf maxage-list
@sh ip ospf delete-list
@sh ip ospf statistic
@sh ip ospf bad-checksum
@sh ip ospf event
@sh isis timers
@sh isis tree IS-IS link state database AVL tree
@sh isis tree level-2
@sh isis private
@sh profile [detail|terse] (show cpu profiling)
@sh parser modes (shows current process access-tree.)
@sh parser unresolv (shows unresolved links in access-tree)
@sh list
@sh list none
@sh region (shows image layout)
@sh region <address> (shows image layout at given address)
@sh timers (show timers for timer command in config mode)
@sh int <INT> switching (shows switching path information for the interface)
@sh proc all-events (shows all process events)
@sh sum (show current stored image checksum)
@test transmit (test the transmission of L2 frames)
configuration mode commands
@boot system rom
@boot module
@exception-slave dump X.X.X.X
@exception-slave protocol tftp
@exception-slave corefile
@ip route profile
@ip slow-convergence
@ip tftp boot-interface
@loopback diag
@loopback dec (at dec chip)
@loopback test
@loopback micro-linear
@loopback motorola
@scheduler max-task-time 200 (last val in milliseconds)
@scheduler heapcheck process (memory validation.. after proc)
@scheduler heapcheck poll (memory valid after some poll)
@scheduler run-degraded (perhaps in a failure mode?)
@service internal
@service slave-coredump
@service log backtrace (provides traceback with every logging instance)
@tunnel carry-security
in bgp config:
@neighbor ctalkb-out filter-as 100 d
% filter-as is an obsolete subcommand, use filter-list instead
in router isis config:
@partition-avoidance
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
@clear profile
clears out the current CPU profiling configuration.
@debug buffer
as with buffer sanity checking, no debugging information on lightly
loaded box.
ctalkb#debug buffer
Additional buffer checking debugging is on
@debug ip ospf monitor
provides information on the status of the ospf process in the debugging
logs.
ctalkb#debug ip ospf monitor
OSPF spf monitoring debugging is on
2w3d: OSPF: Syncing Routing table with OSPF Database
-Traceback= 6064B628 603B6D2C 603B6D18
2w3d: OSPF: Completed Syncing and runtime is 4 msec
-Traceback= 6064B65C 603B6D2C 603B6D18
2w3d: OSPF: Start redist-scanning
-Traceback= 6064AC20 6062B430 603B6D2C 603B6D18
2w3d: OSPF: Scan for both redistribution and translation
-Traceback= 6064AC60 6062B430 603B6D2C 603B6D18
2w3d: OSPF: End scanning, Elapsed time 0ms
-Traceback= 6064B13C 6062B430 603B6D2C 603B6D18
2w3d: OSPF: Syncing Routing table with OSPF Database
-Traceback= 6064B628 603B6D2C 603B6D18
ctalkb#debug oir
Online Insertion and Removal debugging is on
2w3d: OIR: Process woke, ‘Event’, stall=2, usec=0xB6835B36
-Traceback= 6040967C 603B6D2C 603B6D18
2w3d: OIR: Shutdown pulled interface for Serial5/0
-Traceback= 600E30C4 60409204 604096C8 603B6D2C 603B6D18
2w3d: %OIR-6-REMCARD: Card removed from slot 5, interfaces disabled
-Traceback= 60409748 603B6D2C 603B6D18
2w3d: OIR: Remove hwidbs for slot 5
-Traceback= 60409368 60409750 603B6D2C 603B6D18
2w3d: OIR: Process woke, ‘Event(max not running)’, stall=3,
usec=0xD0115C9E
-Traceback= 6040967C 603B6D2C 603B6D18
2w3d: OIR: Process woke, ‘Timer(max running)’, stall=3, usec=0xDDBB56D6
-Traceback= 6040967C 603B6D2C 603B6D18
2w3d: OIR: (Re)Init card 5, retry_count=3
-Traceback= 60409894 603B6D2C 603B6D18
2w3d: %OIR-6-INSCARD: Card inserted in slot 5, interfaces administratively
shut down
-Traceback= 604098BC 603B6D2C 603B6D18
@debug par mo (debug parser modes)
this is used to show what is happening at the parser at specific
instances. it will show you a basic walkthrough of the lookups needed
to process the cli commands
ctalkb#debug par mo
Parser mode debugging is on
00:54:40: Look up of parser mode ‘controller’ succeeded
00:54:40: Look up of parser mode ‘route-map’ succeeded
@debug sanity
couldn’t get any diagnostic information on this. router is not
heavily loaded so there isn’t much buffer churn and burn to
contend with.
ctalkb#debug sanity
Buffer pool sanity debugging is on
@debug subsys
subsystem information indicates a code segment and its version. when
i had debugging on, i tried reloading the system microcode. this did
not cause any interesting debugging information.
ctalkb#debug sub
Subsystem debugging is on
@debug oir
extended online insertion and removal debugging information.
@gdb kernel
i couldn’t get this to do much besides render the router inoperable.
there seems to be no interface comparable to the stock gnu debugger.
perhaps there are additional parameters that i am missing. this applies
to all of the debugger subcommands found.
ctalkb#gdb ker
Kernel GDB allowed on console terminal only
ctalkb#gdb ex 91
||||(lock up)
@gdb debug pid
ctalkb#
ctalkb#gdb debug 91
Can’t debug your own process
ctalkb#
@if-console [<slot>] [console|debug]
no output since i don’t have a viper router or 12XXX. however,
this is one of the most interesting hidden commands available for the
cisco. it allows you to get on a card console (i.e. per individual slot
instead of per individual chassis) and print out extended diagnostic
and debugging information on the specific card. you enter the card
in unpriv mode and need to enable before seeing all of the commands.
@profile <start> <stop> <granularity>.
you can setup cpu profiling in the exec mode with the
profile command. process profiling allows you to find which segment
of code is perhaps hogging the CPU.. what you really need to get use
out of this feature is a symbol table so you can pull the location of
the appropriate segment of code. the segment is defined by the start
and stop values given to the profile command. the granularity specifier
allows you to get down to single instruction level.
the cpu has its own internal timer that is incremented regardless
of whether the desired segment of code is executed. when the desired
segment of code is executed, a per-profile counter is incremented.
comparison of this counter with the overall system timer allows you to
get some handle on how much of the cpu the specific segment is using.
ctalkb#profile ?
task
start
stop
hogs
<0-FFFFFFFF>
@show chunk (show chunks of memory allocated to processes)
there is the traditional malloc/free memory management in place
on the cisco. there is also chunk allocation. the main benefit
of chunk allocation over its predecessor is that memory overhead
is only paid by the large chunk (which is then carved up into
smaller pieces) instead of by each individual malloced block.
ctalkb#sh chunk
Chunk Manager:
142 chunks created, 1 chunks destroyed
46 siblings created, 0 siblings trimmed
Chunk element Block Maximum Element Element Total
cfgsize Ohead size element inuse freed Ohead Name
16 0 65532 3270 717 2553 8 List Elements
0x61525688
52 0 65532 1168 0 1168 0 List Headers
0x61535684
16 0 65532 3270 0 3270 8 messages 0x61550068
@show chunk summ
summary listing of allocated chunks. shows you big chunk size, the
number of siblings divided up within that chunk space as well as
the overhead taken by the chunk.
ctalkb#sh chunk sum
Chunk Manager:
142 chunks created, 1 chunks destroyed
46 siblings created, 0 siblings trimmed
Element Sibling size Total Total Total Inuse Ovrhd Chunk
Flag size(b) –range(b)– Siblg alloc Free HWM (b) name
D 16 253- 752 0 3270 2553 724 8 ListElements
D 52 1003- 1502 0 1168 1168 0 0 List Headers
D 16 253- 752 0 3270 3270 21 8 messages
D 8 253- 752 0 5450 3974 1476 8 Reg Function
8
@sh idb
This command shows the hardware and software interface databases.
this is cisco’s way of keeping track of how many interfaces are present
on the system.. includes hardware and software interfaces (physical,
subinterfaces etc). there is a software limit of 1024 i believe in
ios 11 and 2048 in ios 12. this is a global limit for the router.
output:
ctalkb#sh idb
19 SW IDBs allocated (2296 bytes each)
9 HW IDBs allocated (4008 bytes each)
HWIDB#1 1 FastEthernet0/0 (Ether)
HWIDB#2 2 Serial2/0:0 (Serial)
HWIDB#3 3 Ethernet3/0 (Ether)
HWIDB#4 4 Ethernet3/1 (Ether)
HWIDB#5 5 Ethernet3/2 (Ether)
HWIDB#6 6 Ethernet3/3 (Ether)
HWIDB#7 7 Serial4/0 (Serial)
HWIDB#8 8 Serial5/0 (Serial)
HWIDB#9 9 Loopback0
@sh in stats (gives you switching path output per interface)
Ethernet3/0
Switching path Pkts In Chars In Pkts Out Chars Out
Processor 786433 594121827 556812 177400752
Route cache 107469 8910774 107451 8925784
Total 893902 603032601 664263 186326536
@sh int e3/0 switching
goes over some of the basic processes and the data that they are
processing. shows what switching paths were used for the specific
data counted. basic processes == IP and routing processes. others
are lumped into the default category.
ctalkb#sh int e3/0 switching
Ethernet3/0
Throttle count 0
Drops RP 0 SP 0
SPD Flushes Fast 0 SSE 0
SPD Aggress Fast 0
SPD Priority Inputs 972 Drops 0
Protocol Path Pkts In Chars In Pkts Out Chars Out
Other Process 0 0 167 10020
Cache misses 0
Fast 0 0 0 0
Auton/SSE 0 0 0 0
IP Process 4556 282352 3733 541124
Cache misses 0
@sh ip ospf maxage-list
don’t have ospf running.. would seem that this command shows you
the current value of the max-lsa age. there is some periodic refresh
which needs to be accounted for.
ctalkb#sh ip ospf max
AS System N
Maxage delete timer due in NEVER
@sh ip ospf delete-list
this command shows you the lsas which have been deleted from
consideration. as i don’t have ospf running, i can’t ascertain whether
this is lsas which were taken out of consideration by the SPF algorithm
or by other means.
ctalkb#sh ip ospf delet
AS System N
Area BACKBONE(0)
ROUTER and NETWORK LSDB delete list
Dest: 172.16.0.1, Type: 0, Metric: 1, ADV RTR: 172.16.0.1
Path:
gateway 172.16.0.1, interface Loopback0
SUMMARY NET and ASBR LSDB delete list
TYPE-7 EXTERNAL LSDB delete list
EXTERNAL LSDB delete list
@sh ip ospf statistic
this is a really handy command because it gives you time averages of
different portions of the ospf process. this is useful in that it further
lets you pin down IGP convergence times on your network as well as to
isolate the areas which are causing the process to chug.
ctalkb#sh ip ospf stat
Area 0: SPF algorithm executed 1 times
SPF calculation time
Delta T Intra D-Intra Summ D-Summ Ext D-Ext Total Reason
2w3d 0 0 0 0 0 0 0 R,
Avg. and Accumulated time of the last 250 process_ase()
Avg. Accumulated
ASBR-lookup 0, 0
Forw-Addr-lookup 0, 0
compare metric 0, 0
… (more)
@sh ip ospf bad-checksum
shows LSAs which have failed the checksum.
not sure if this is a count or actual event times since i didn’t
have ospf functioning.
@sh ip ospf event
provides a history lists of subprocess function execution.. useful so that
the operator can understand a bit more about the execution flow
ctalkb#sh ip ospf eve
1 54700 Generic: ospf_redist_callback 0x618B36A4
2 114716 Generic: ospf_redist_callback 0x618B36A4
3 174736 Generic: ospf_redist_callback 0x618B36A4
4 234756 Generic: ospf_redist_callback 0x618B36A4
5 294772 Generic: ospf_redist_callback 0x618B36A4
6 320796 Generic: ospf_build_ex_lsa 0xC658FF00
7 320796 Generic: ospf_build_ex_lsa 0xAC100000
8 320796 Generic: ospf_build_ex_lsa 0xD16F5C00
@sh isis timers
useful in that it provides a brief overview of execution flow
in the isis process. shows you frequency of things like l1/l2 hello
etc.
ctalkb#sh isis timers
Hello Process
Expiration Type
| 0.856 (Parent)
| 0.856 L2 Hello (Ethernet3/0)
| 6.352 L1 Hello (Ethernet3/0)
| 6.940 Adjacency
Update Process
Expiration Type
| 1.060 (Parent)
| 1.060 Ager
| 1.352 L2 CSNP (Ethernet3/0)
| 8.616 L1 CSNP (Ethernet3/0)
| 3:25.860 (Parent)
| 3:25.860 LSP refresh
| 9:02.160 LSP lifetime
| 9:24.568 LSP lifetime
| 17:16.084 LSP lifetime
| 20:58.536 Dynamic Hostname cleanup
@sh isis tree IS-IS link state database AVL tree
shows path and depth taken to get to other level 1/2 intermediate
systems in some routing domain. shows both by default.
ctalkb#sh isis tree
IS-IS Level-2 AVL Tree
Current node = X.X.X.00-00, depth = 0, bal = 0
Go down left
Current node = X.X.Y.00-00, depth = 1, bal = 0
—> Hit node X.X.Y.00-00
Back up to X.X.X.00-00
Current node = X.X.X.00-00, depth = 0, bal = 0
—> Hit node X.X.X.00-00
Go down right
Current node = X.X.X.02-00, depth = 1, bal = 0
—> Hit node X.X.X.02-00
Back up to X.X.X.00-00
@sh isis private
displays a little diagnostic information related to the isis process.
ctalkb#sh isis private
ISIS: FastPSNP cache (hits/misses): 0/4002
ISIS: LSPIX validations (full/skipped): 216271/490412
ISIS: LSP HT=0 checksum errors received: 0
ctalkb#
@sh list
perhaps a singly linked list manager which displays global
pointer to the first element in each linked list as well as the
number of members in each list.
ctalkb# sh list
List Manager:
1415 lists known, 1561 lists created
ID Address Size/Max Name
1 613EE970 11/- Region List
2 613EEE98 1/- Processor
3 613EFDE8 1/- I/O
4 613F0D38 1/- I/O-2
5 6149EDD0 0/- Sched Critical
6 6149ED90 0/- Sched High
7 6149EB00 0/- Sched Normal
@sh list none
ctalkb# sh list none
List Manager:
1415 lists known, 1561 lists created
ID Address Size/Max Name
1 613EE970 11/- Region List
2 613EEE98 1/- Processor
3 613EFDE8 1/- I/O
4 613F0D38 1/- I/O-2
9 6149ED10 82/- Sched Idle
11 61499A50 8/- Sched Normal (Old)
12 6149CC10 1/- Sched Low (Old)
@sh parser modes (shows current process access-tree.)
ctalkb#sh par mo
Parser modes:
Name Prompt Top Alias Privilege
exec 0x60EFB294TRUE TRUE
configure config 0x60EFABACTRUE TRUE
interface config-if 0x60EF7AECTRUE TRUE
subinterface config-subif 0x60EF7AECTRUE FALSE
null-interface config-if 0x60EFB368TRUE TRUE
line config-line 0x60EF3F84TRUE TRUE
@sh parser un
ctalkb#sh parser un
Unresolved parse chains:
40
40
198
198
322
@sh proc all-events
ctalkb#sh proc all-events
Queue Notifications
Event Name Pid 1 Process
61588410 Pool Grows 4 Pool Manager ct
0
615A156C Log Messages 19 Logger ct
0
615EE8A0 IPC inboundQ 11 IPC Seat Manager ct
0
615EE934 IPC Zone inboundQ 9 IPC Zone Manager ct
0
61642840 ARP queue 12 ARP Input ct
0
@sh profile [detail|terse] (show cpu profiling)
ctalkb#sh prof d
Profiling enabled
Block 0: start = 91, end = FFF, increment = 8, EXEC
Total = 0
System total = 9802
ctalkb#sh prof t
PROF 91 FFF 8
PROFTOT 10065
ctalkb#
@sh region (shows image layout)
displays the program layout for the uncompressed image.
ctalkb#sh region
Region Manager:
Start End Size(b) Class Media Name
0x07800000 0x07FFFFFF 8388608 Iomem R/W iomem2
0x20000000 0x21FFFFFF 33554432 Iomem R/W iomem
0x57800000 0x57FFFFFF 8388608 Iomem R/W iomem2:(iomem2_cwt)
0x60000000 0x677FFFFF 125829120 Local R/W main
0x60008900 0x6123AC29 19079978 IText R/O main:text
0x6123C000 0x6136A17F 1237376 IData R/W main:data
0x6136A180 0x6152565F 1815776 IBss R/W main:bss
0x61525660 0x677FFFFF 103655840 Local R/W main:heap
@sh region <address>
picking a random location within memory shows what segment that
specific address falls under. same info can be gleaned from the
root command.
ctalkb#sh region a 0x07800000
Address 0x07800000 is located physically in :
Name : iomem2
Class : Iomem
Media : R/W
Start : 0x07800000
End : 0x07FFFFFF
Size : 0x00800000
@sh sum
this takes the compressed image and computes its checksum. this is
compared with the previously stored checksum to ensure integrity.
ctalkb#sh sum
New checksum of 0x36D03E96 matched original checksum
ctalkb#
@sh timers (show timers for timer command in config mode)
ctalkb#sh tim
State Handle interval due invoked missed Process
@test transmit (test the transmission of L2 frames)
this command allows you to send the specified number of frames
to the specified destination:
ctalkb#test transmit
interface: Ethernet3/0
total frame size [100]:
1) To this interface
2) To another interface
9) Ask for everything
Choice: 2
Encapsulation Type:
1) Ethertype
2) SAP
3) SNAP
4) SNAP (Cisco OUI)
5) SNAP (EtherV2 OUI)
6) Novell 802.3
Choice: 1
Protocol type:
1) IP
2) XNS
3) IPX
9) Ask for everything
Choice: 1
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
(in config mode)
@boot system rom
if the system has an image burned in on rom, this command allows you to
revert to that image instead of the image stored on some other secondary
media (flash card).
ctalkb(config)#boot system rom
The ‘boot system rom’ command is not valid for this platform.
It has been translated to ‘boot system flash bootflash:’
@boot module
the command is there, but it doesn’t seem to do anything besides barf.
00:34:02: %PARSER-3-BADSUBCMD: Unrecognized subcommand 11 in configure
command ‘boot module a’
@exception-slave dump X.X.X.X
informs the router where to dump the core image.
@exception-slave protocol tftp
tells the router what protocol to use when dumping the core image.
@exception-slave corefile
tells the router what to name the corefile. note that this corefile
has to be at least 666 on the tftp server for the router to be able to
write it.
@ip slow-convergence
i haven’t been able to see any difference in the router performance after
enabling this command. regardless, it does not look like a command which
would improve the router performance.
@ip tftp boot-interface
tells the router what interface to find its image in the case that it
wants to boot net via tftp.
@loopback diag
all of these loopback commands allow you to loop the hardware at
specific points so that you can isolate hardware faults. e.g. this
is not just a loopback net and loopback local command set. also,
not all pieces of hardware can be looped at all the below points.
@loopback dec (at dec chip)
@loopback test
@loopback micro-linear
@loopback motorola
@scheduler max-task-time 200 (last val in milliseconds)
this knob allows you to set the number of milliseconds a specific
process is on CPU before it reports debugging information. a relatively
easy way to report which process is hogging. sh proc cpu is obviously
the best way to track down cpu hogs while on the router, but this command
allows you to track down more insidious hogs.
00:13:18: %SYS-3-CPUHOG: Task ran for 308 msec (3/1), process = Virtual
Exec, PC = 603C9AD8.
@scheduler heapcheck process (memory validation.. after proc)
@scheduler heapcheck poll (memory valid after some poll)
@scheduler run-degraded (perhaps in a failure mode?)
causes the scheduler to attempt to keep running even in the face of some
sort of fatal process error. the default action of IOS is to have this
knob turned off and to crash the router upon the recognition of a fatal
error. this is done on a per-process basis. obviously, some processes
are more critical than others and moving the offending process out of the
scheduler won’t really buy you any time or information.
@service internal
this is a really nifty command. turning it on in global configuration
mode allows you to view some previously hidden commands. turn it on
by default and you will eventually find some extras.
some commands are not even accessible unless this is turned on.
(sh proc all-events fex)
@service slave-coredump
this allows you to dump core when applicable to some slave
machine for logging purposes. this does take a long time depending
on the amount of memory in the router (copying 128MB with varying
link speeds. you do the math). it is important to note that this
copying occurs before the router enters usable mode, so you basically
have added quite a bit of delay into the reload time. the
exception-slave commands inform the router where to dump the core image.
@service log backtrace (provides traceback with every logging instance)
-Traceback= 603C9AE0 603546C0 60354A48 6035CA58 6035C3F4 6035C34C 60373EBC
603B6D2C 603B6D18
in bgp config:
@neighbor ctalkb-out filter-as 100 d
% filter-as is an obsolete subcommand, use filter-list instead
this is a nifty command in that it gives you a little more insight
into whats happening. i would prefer this command even though it
has been deprecated in favor of the filter-list command. reasoning:
this command is more specific.
in router isis config:
@partition-avoidance
not quite sure what this does since i don’t have a complex isis setup to test.
Comé você então, gajo? 