3750G won't "age out" old arp table entries

WS-C3750G-24TS running
12.2(20)SE4, RELEASE SOFTWARE (fc1).
sho mac-address-table aging-time
Vlan Aging Time
253 300
252 300
254 300
255 300
1 300
251 300
The aging is not working. I can failover some devices I have and the mac-address of the old device associated the the IP never ages out. "Clear arp" makes the standby unit respond to pings and connectivity to the standby unit is 100% after the "clear arp".
Showing the arp cache, I can see the IP associated with the old mac-address and the "age" keeps increasing, not decreasing with the old mac-address.
It also doesn't matter if the Primary unit has been rebooted, switch keeps the old mac-address associated the Primary unit.
Suggestions?

I think permanent entry should have been made into the arp cache using the "arp ip-address hardware-address type" command.
To remove this arp entry, you can try "clear arp-cache".This will delete all dynamic entries from the ARP table.
for more details, refer the following page:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_command_reference_chapter09186a00800ca5b0.html#1017562

Similar Messages

Delete ARP table entry

I need to create a program to delete an entry in the ARP table in Windows 7 with LabVIEW or TestStand. The test that I am developing communicates with the DUT over Ethernet. Each DUT has the same IP address to start but different MAC addresses. I am noticing that there can be long delays in the test execution when trying to connect and deleting the previous entry in the ARP table seems to help. But currently I have to do this manually through the command line. The command "arp -d" requires elevated privileges. I have been having a tough time getting LabVIEW to elevate the system exec. Does anybody have an ideas? Is there any .NET access to the ARP table?
Thanks,
Paul
Solved!
Go to Solution.

I would try looking into tuning the ARP timing parameters in Windows.
We suffered from various TCP performance/connection problems some years ago and our solution was to modify the the default number of TCP sockets and timeouts (we were experiencing port exhaustion). The tweeks eliminated most of our problems, no LV/TS code changes required.
I tried to find info on ARP settings for Windows 7, but it seems that there is much less info available than ther is for XP.
The registry keywords most common for older versions of Windows were "ArpCacheLife" and "ArpCacheMinReferencedLife"
EDIT:
These settings were apparently removed in Vista. I found this on the M$ site; they may apply to later versions as well since M$ is following an RFC for ARP management...
http://support.microsoft.com/kb/949589
Now is the right time to use %^<%Y-%m-%dT%H:%M:%S%3uZ>T
If you don't hate time zones, you're not a real programmer.
"You are what you don't automate"
Inplaceness is synonymous with insidiousness

How to find out log for table entry deletion.

Hi Guys,
Somebody has deleted entire MARC in one of our systems. Is there any way to find out who deleted the entries?
Thanks

Use CDPOS and CDHDR to know who changed/deleted
from CDPOS .. get the OBJECTCLAS   OBJECTID     and
CHANGENR     passing TABNAME    as MARC
Pass the above OBJECTCLAS   OBJECTID     and
CHANGENR to CDHDR and get USERNAME

Undo segments won't age out

on my Oracle 11.2.0.2, I have undo tablespace, and db init settings like:
recyclebin=off
flasbach_on=off
undo_retention=1200
undo_management=AUTOI have a table aa_test with 1 million rows..
after I invoke a sql like:
update aa.test set n_string='aaa';
commit;undo segment just do not want to be freed..
I created undo tablespace using:
CREATE UNDO TABLESPACE UNDOTBS1 DATAFILE
'/opt/oracle/oradata/bongo/undotbs01.dbf' SIZE 200M reuse AUTOEXTEND ON NEXT 50M MAXSIZE 10240M
ONLINE
RETENTION NOGUARANTEE
BLOCKSIZE 8K
FLASHBACK OFF;

sql statement is:
update aa_test set n_string='abc';
commit;before update undo tablespace looks like:
SQL> select usn, rssize from v$rollstat;
       USN     RSSIZE
      0     385024
     11     122880
     12     122880
     13     122880
     14     122880
     15     122880
     16     122880
     17     122880
     18     122880
     19     122880
     20     122880after updates (commit and logout/logon)
SQL> select usn, rssize from v$rollstat;
       USN     RSSIZE
      0     385024
     11     122880
     12     122880
     13     122880
     14     122880
     15     122880
     16 176152576
     17     122880
     18     122880
     19     122880
     20     122880

Phone won't dial out. Old phone received missed calls yesterday instead of my new phone.

Current phone suddenly won't dial out. Yesterday my old phone (which I use for WiFi only and which has not been activated for about 1 year) started receiving calls instead of my current phone. I was not around to answer them, but they only registered as missed calls on my old phone.
Today I tried making a call and my current phone won't dial out--trying to dial any number just gives me silence and then it disconnects after 30 seconds or so. I tried dialing out on the old phone, but it gives me a roaming message and wants me to either buy a calling PIN or call collect to dial out. On my current phone I can still use data/internet fine and I think texting still works (tested by texting my own number and I received the text).
I've tried powering off the old phone for a while and then restarting the new phone, but it didn't help... I can't call verizon since I can't dial out and its saturday night so it looks like their chat is offline..
How can I fix this? Help is greatly appreciated!

Thanks for the reply.
Unfortunately *611 does not work -- like all numbers I try to dial, it goes to the "dialing" screen then does nothing for about 30 seconds, then it disconnects.
*228 Brings up a message box that says "a verizon wireless sim card has activated your service and updated your phone's roaming capabilities. Your phone number is [my number]" The problem is not fixed however.
I should also clarify that I have been using my old phone for wifi/mp3 playing just fine for the past 1 year without experiencing this problem ever before. My current/newer phone has been working fine right next to it all that time. I did just pull my old SIM card out of my old phone just now in case that might help (should have done that a long time ago). I also removed the battery. That was several hours ago, still having the problem after rebooting the new phone and testing many times.
Using another person's phone I have now verified that I can't make or receive any calls on my new phone, but I can send and receive text messages as well as use mobile data/internet. The newer phone is an LG G2 and the old phone is a Galaxy Nexus if that matters.
Thanks for the help so far

Host not showing up in ARP table

Hi,
I am having an interesting/weird problem with one of my Catalyst 6509 switches.
The setup is as follows:
HostA - Switch1 - Switch2 - HostB
There is routing in place for HostA to reach HostB and vica versa.
I am testing this using ICMP. There is nothing blocking ICMP traffic on any of the devices.
Problem in question: I can only ping HostB from HostA (or Switch1) if HostB is found in the ARP table of Switch2. Pretty normal you might say since we need Switch2 to route/switch the packet to HostB and that will of course only happen if the ARP table is populated.
But what happens is the following:
I ping from HostA to HostB. It fails. I check Switch2 and I see that HostB is nowhere to be found in its ARP table.
Next I ping HostB from Switch2 (5 packets). First packet fails, last 4 I get a reply. I check and see that now HostB is to be found in the ARP table of Switch2.
Now I ping HostB from HostA and it works fine.
This behaviour is happening for all hosts in the subnet (VLAN) of HostB. I cannot reach them until I ping them from Switch2, after which they're in the ARP table and everything works.
Maybe it something different than the ARP table not being populated all together, but that is for now all I noticed. Does this problem ring a bell with anyone. And is there a fix?
It looks to me like Switch2 is malfunctioning, although I have no idea what is. Furthermore this apears to be working ok for a lot (read: all) of the other VLANS on Switch2.
Anyway. I'd love some help in troubleshooting this one.
kind regards,
Kevin

This goes back to the way switches (or bridges) work. They have to see a frame from an end device to know its MAC address and once they see it they add an entry in their CAM (or MAC) table. The entry basically tells the switch that a specific MAC is reachable via a particular port and this is meant to prevent subsequent flooding of unicast frames. In short an end device needs to send at least one frame for the switch to 'see' it. Another point to remember is that each entry in the CAM table has an age associated with it and if a switch does not see subsequent frames from that host it will age out the entry and start flooding all frames destined to this MAC address until it is learnt again (and learning is done only when the owner of the MAC starts to communicate again).
Kevin,
Can you please explain your topology in a bit more detail? I am looking for information like what is the default gateway of each VLAN, how are the VLANs spread across the two switches, any HSRP configurations and if yes who is the active for what VLAN, routing between switches, etc. This will help us troubleshoot the problem in a more effective manner.

Sending Ciscowrks device credential Verification Job alters the device ARP table.

Hi:
I send a Device credential verification Job to two different devices , a Cisco 3750 and a blade switch WS-CBS3120. I configured SNMP write access to the switches. The SNMP write access in either SNMP v1 or SNMP V3 , tried both.
The job is send from the Ciscoworks server.
Once the job has completed, I do a show ip arp on the device and find a new entry with the IP address of the Ciscoworks Server and the mac-address of the L2 next hop.
We would not have noticed this behavior had it not been that in the case that the switch next hop is an HSRP vlan on a nexus , the ARP entry entered into the switch is incorrect, and from then on the switch loses connection to Ciscoworks.
The Mac-address that is entered by Ciscoworks , in the case of nexus is a statice mac defined on the Nexus for the Vlan in question , but it is NOT the HSRP default gateway MAC address. Therefore we lose connection between the switch and Ciscoworks. One has to manually clear the ARP table inorder to again reach the Ciscoworks.
Questions:
1. Why does Ciscoworks insist on changing the ARP table?
2. Is this ARP entry aged out or is it permeant as would an ARP entry which is entered through CLI be permeant ?
3. In the case of the Nexus connection, this ARP entry does not allow Ciscoworks and the device to communicate. This is not productive!
Has any one come across this situation ? Any known fixes, workarround? I was not able to find a word about this on Cisco's site.
Our Ciscoworks is at the following levels:
CW Common services    3.3.0
LMS portal                    1.2.0
CW Assistent                1.2.0
RME                             4.3.1
Device fault manager      3.2.0
IPM                              4.2.1
Cisco View                    6.1.9
campus Manager            5.2.1
thanks   for any help
Mickey

CiscoWorks does not change the ARP table, at least not overtly. A credential verification job will do the following things depending on what protocols are selected to test:
SNMP RO : Fetches sysLocation.0
SNMP RW : Sets sysLocation.0 to the value currently stored in sysLocation.0
Telnet : Logs in using DCR username and password
SSH : Logs in using DCR username and password
Enable : Enters enable mode and verifies privilege level 15
If one of these things are causing the ARP table to change, then there is something fishy in the device or network configuration. I've never heard of such behavior relating to CiscoWorks before.

ARP table not populating mac address for previously reachable IP address

Router has been online and working fine with one BGP neighbor for almost 2 years and no downtime. 2 weeks ago, added a 2nd BGP peer. Everything worked fine for 2 weeks, then all of a sudden yesterday the 2nd BGP peer is disconnected and does not come back. ISP checks and sees everything looks fine on their end. We cannot even ping each other now.
Upon investigation, the ARP table is not even populating the MAC address for the BGP peer IP anymore (same local subnet). Stays "incomplete" in the table no matter what we do, including clearing arp table, changing IP address, etc.
Plug a laptop directly into the 2nd BGP peer FE port and replicate the IP addressing. Laptop cannot ping Router, but Router CAN ping laptop. Check ARP table, but STILL no mac address assigned and now not even the ARP table showing "incomplete".
Thinking it could be the FE interface, switch to the 2nd FE interface and perform same laptop test, this time with arbitrary IP addressing. Now cannot ping each other, no MAC in ARP table.
End up rebooting the router and lo-and-behold, everything is working normally again. 2nd BGP peer peers up instantly.
I should also mention that the 1st BGP peer worked flawlessly throughout, taking all the Internet load and having no issues throughout.
Also, the FE ports for the 2nd BGP peer are on an HWIC FE card plugged into the router. The 1st BGP peer is plugged into the built-in GE interface. 2901 running: c2900-universalk9-mz.SPA.151-4.M4.bin
Lastly, no router resource issues, no error messages, no logs. Just the BGP peer disconnecting.
I have never, in 20 years working with Cisco routers seen something like this before. This is the most fundamental aspect of IP and Ethernet that was not working.
Has anyone ever seen this behavior before??
Here is the router config (IP's changed):
version 15.1
service timestamps debug datetime msec localtime show-timezone
service timestamps log datetime msec localtime show-timezone
service password-encryption
service internal
service sequence-numbers
boot-start-marker
boot-end-marker
logging buffered 150000
aaa new-model
aaa authentication login LAUTHEN local
aaa authentication login TAUTHEN local group tacacs+ enable
aaa authorization console
aaa authorization exec LAUTHOR local if-authenticated
aaa authorization exec TAUTHOR local group tacacs+ if-authenticated
aaa session-id common
clock timezone PST -8 0
clock summer-time PDT recurring
no ipv6 cef
no ip source-route
ip cef
no ip domain lookup
multilink bundle-name authenticated
username ubiadmin privilege 15 secret 4 .JbeuWXuZvchrG0OL.5BftFtqrrEyxcnVHn5rIuCnTk
username umitsnoc01 privilege 15 secret 4 cUmoRUjey9O1x.wk9S.kleX.iAAhCwihupr6Z98p6OA
redundancy
ip ssh version 2
track 1 interface GigabitEthernet0/0 line-protocol
class-map match-any AutoQoS-VoIP-RTP-Trust
match access-group name SIP-Media-INBOUND
class-map match-any AutoQoS-VoIP-Control-Trust
match ip dscp cs3
match ip dscp af31
class-map match-any Customer-Voice
match access-group name Customer-VPNs
class-map match-any media
match access-group name SIP-Media
class-map match-any signaling
match access-group name SIP-Signaling
policy-map AutoQoS-Policy-Trust
class AutoQoS-VoIP-RTP-Trust
priority percent 70
class AutoQoS-VoIP-Control-Trust
bandwidth percent 5
class class-default
fair-queue
policy-map queue
class signaling
bandwidth percent 5
class media
priority percent 50
class Customer-Voice
priority percent 40
class class-default
fair-queue
policy-map shape
class class-default
shape average 10000000
service-policy queue
interface Embedded-Service-Engine0/0
no ip address
shutdown
interface GigabitEthernet0/0
description BGP Peer 1
ip address 2.2.2.2 255.255.255.252
no ip redirects
ip flow ingress
ip flow egress
duplex auto
speed auto
service-policy output shape
interface GigabitEthernet0/1
description LAN
ip address 1.2.3.4 255.255.255.0
no ip redirects
ip flow ingress
ip flow egress
standby 255 ip 1.2.3.1
standby 255 priority 105
standby 255 preempt
standby 255 mac-address 1a2b.3c4d.5e6f
standby 255 track 1 decrement 10
duplex auto
speed auto
service-policy output AutoQoS-Policy-Trust
interface FastEthernet0/0/0
description BGP Peer 2
ip address 1.1.1.1 255.255.255.252
ip flow ingress
ip flow egress
duplex full
speed 100
service-policy output shape
interface FastEthernet0/0/1
no ip address
shutdown
duplex auto
speed auto
router bgp 7777
bgp router-id 2.2.2.2
bgp log-neighbor-changes
network 1.2.3.0 mask 255.255.255.0
neighbor 1.1.1.2 remote-as 5555
neighbor 1.1.1.2 update-source FastEthernet0/0/0
neighbor 1.1.1.2 prefix-list L3-DEFGW in
neighbor 1.1.1.2 route-map L3-LPREF-IN in
neighbor 2.2.2.1 remote-as 6666
neighbor 2.2.2.1 ebgp-multihop 2
neighbor 2.2.2.1 update-source GigabitEthernet0/0
neighbor 2.2.2.1 send-community
neighbor 2.2.2.1 prefix-list COLO-DEFGW in
neighbor 2.2.2.1 route-map COLO-LPREF-IN in
neighbor 2.2.2.1 route-map COLO-OUT out
ip forward-protocol nd
ip bgp-community new-format
ip as-path access-list 5 permit _5555_
ip as-path access-list 5 deny .*
ip as-path access-list 10 permit ^6666$
no ip http server
no ip http secure-server
ip flow-top-talkers
top 50
sort-by bytes
ip route 0.0.0.0 0.0.0.0 1.1.1.2 254 name L3
ip route 0.0.0.0 0.0.0.0 2.2.2.1 255 name COLO1
ip route 10.0.0.0 255.0.0.0 10.10.10.10 name FW_OUTSIDE
ip tacacs source-interface GigabitEthernet0/1
ip access-list standard SNMP_SOURCES
permit 12.12.12.0 0.0.0.255
deny any log
ip prefix-list L3-DEFGW seq 5 permit 0.0.0.0/0
ip prefix-list COLO-DEFGW seq 5 permit 0.0.0.0/0
ip prefix-list COLO-LPREF-OUT seq 5 permit 1.2.3.0/24
route-map COLO-LPREF-IN permit 5
match as-path 5
set local-preference 250
route-map COLO-LPREF-IN permit 10
set local-preference 150
route-map COLO-LPREF-IN permit 20
route-map COLO-OUT permit 10
match ip address prefix-list COLO-LPREF-OUT
set as-path prepend 7777 7777 7777
set community 29795:1004
route-map COLO-OUT permit 20
route-map L3-LPREF-IN permit 10
match as-path 10
set local-preference 200
route-map L3-LPREF-IN permit 20
set local-preference 150
snmp-server enable traps snmp authentication linkdown linkup coldstart warmstart
snmp-server enable traps vrrp
snmp-server enable traps flowmon
snmp-server enable traps transceiver all
snmp-server enable traps ds1
snmp-server enable traps call-home message-send-fail server-fail
snmp-server enable traps tty
snmp-server enable traps license
snmp-server enable traps envmon
snmp-server enable traps ethernet cfm cc mep-up mep-down cross-connect loop config
snmp-server enable traps ethernet cfm crosscheck mep-missing mep-unknown service-up
snmp-server enable traps flash insertion removal
snmp-server enable traps mac-notification
snmp-server enable traps aaa_server
snmp-server enable traps cef resource-failure peer-state-change peer-fib-state-change inconsistency
snmp-server enable traps memory bufferpeak
snmp-server enable traps config-copy
snmp-server enable traps config
snmp-server enable traps config-ctid
snmp-server enable traps event-manager
snmp-server enable traps hsrp
snmp-server enable traps cpu threshold
snmp-server enable traps rsvp
snmp-server enable traps syslog
snmp-server enable traps vtp
snmp-server enable traps ipsla

When you were checking the ARP table was there an entry for Fast0/0/0?
HTH
Rick

OMF won't export out of final cut pro.

Exporting a 93min 1920x1080 HD timeline to OMF
5 second handles tried 2 second handles as well.
OMF won't export out of final cut pro. Get error message there is a 2 gb limit.
Final cut 6.0.6
Have deadline. Didn't see it on any forum. Help!! Thanks!!

Seems like a weird thing to not be able to do since it's called final cut PRO...
Bagging on Final Cut Pro for OMF? HA! OMF has been around LONG BEFORE FCP was introduced. It isn't an FCP issue...OMF technology is VERY old. Over 20 years I believe. I used it on Avid...and it always had a 20GB limit.
You cannot deliver 1 track via OMF. You can ask the audio person. I know that Avid now allows you to export an AAF...but FCP doesn't do AAF. For embedded audio I think that OMF is the only way. SO you have to work within the limitations of that format.
Shane

Is there any way so that I Being able to clear out old data from the Order

Hi Friends,
Is there any way so that I Being able to clear out old data from the Order Gate forecast, tolerance, and confirmed order to date tables on a monthly basis?
Means I want data in data table for particular time (I want that if suppose today is 13-11-2008 then my data table must contain data from 13-10-2008 to 13-11-2008.
Is it possible thru ABAP development or thru any t codes ?
Any pointers will be rewarded.
Regards

hi,
Before archiving you have to put the Deletion flag for the object(May be for PO, MMR etc as per your req.)...
After that the you use the archiving procedure to archive the docs which are already flagged for deletion...
For MMR you use the transaction SARA...and its respective object for the archiving....
You can use the SDN search to see the many threads on it...
Or use this link as per your req. and make the search...
http://help.sap.com/saphelp_erp2004/helpdata/EN/75/ee0fa855c811d189900000e8322d00/frameset.htm
Regards
Priyanka.P

Cisco EA4500 ARP Table?

Hello,
I am trying to do the following:
Add a static entry in your router’s ARP table with your device’s MAC address, so it won’t be removed after a time of inactivity (time that depends on the ARP table timeout).
I can't seem to find the ARP table in the settings. Any help would be appreciated.
Thanks

I believe this router doesn't have that feature. Tried searching the net but it’s showing that only business class routers have this feature. This router only has the DHCP client table.

LAN - ARP Table

Hello,
I'm not sure if someone has come across this before. But they might enlighten me.
Under what circumstances would you see ARP enteries on a switch for subnets out side of the local subnet?
Example 2 switches back to back everything in default vlan 1. These uplink to a pair of routers running HSRP.
I would expect to see x.x.x.200 /24
arp enteries for devices on the switches
but not addresses outside of this range.
Any input appreciated.
Thank you.

Suppose you are talking layer2 switches like the 2950 series?
First of all, this has nothing to do with the switching process on the access ports. The arp table on a switch is only used for the IP management interface. ARP entries will appear for anything that you contact from the console.
Typically anything beyond your local subnet is covered by a default gateway but when the switch is using proxy-arp for address resolution you can see anything on your network.
Regards,
Leo

Gratuitous ARPs do not populate the router ARP Table

Hello,
In order to debug an ARP problem in a Firewall cluster environment, I connected a one-armed router on the public VLAN of the firewall cluster, in order to observe the ARP cache behaviour during a switchover. I configured a loopback interface on this router and a default route to this loopback interface to simulate a real router.
When a switchover occurs between firewall cluster members, the active member sends Gratuitous ARPs for all NATed IP addresses. In my environment, I have 110 NATed addresses configured on the firewall.
By launching a "debug arp" on the one armed router, I clearly see all 110 gratuitous ARPs arriving on the router, but the ARP cache of the router is NOT populated with the 110 entries...
Note : The command is configured on the one armed router :
Router(config)# ip arp gratuitous local
What can be the problem ? Is there any condition for a router to accept Gratuitous ARPs ?
Thank you for any help
Yves

Hi
Gratuitous arp is used when a host wants to inform the switch that the mac-address has changed eg.
You have a cluster which has redundant connections and an IP to mac-address mapping. If the active NIC fails the IP address is moved across to the standby NIC but the standby NIC has a different mac-address. So the cluster sends out a gratuitous arp which informs the switch of the new IP to mac-address mapping.
The reason you might not want to allow gratuitous arp is that you might not want your switch updating it's arp table based on annoucements from devices on the LAN as you could very easily spoof mac-addresses and corrupt the arp cache.
HTH
Jon

Esw-540-48 - direclty connected to port 34, still no MAC in ARP table

Hi all,
I have a ESW-540-48 with firmware 2.1.21 (latest)
I have the strangest problem: I can 't find the MAC address of a computer plugged directly on the switch in the ARP table.
I'm trying to search by MAC address, and also by port .
If I reboot the switch, it does work as expected.
Do you think it is software related, and in this case is there anything planned to solve this problem ?
Or maybe I should just replace my hardware ?
Thanks

Hi Firco, it may be possible it is a smart port issue. The ESW switches are very particular to use the correct smart port roles for the connecting devices. I don't think a hardware replacement is warranted unless the given ports absolutely failed to forward.
As a secondary thought, it could also be a spanning tree issue. Ensure you're using RSTP and/or the host ports have port fast enabled. If using classic spanning tree it takes nearly a minute for a port to go to forwarding state. You can disable spanning tree on the port for testing to quickly rule that out.

How to find out whether the tables in SGA?

it's 11.2.0.3.0
Thanks.

IDM99 wrote:
it's 11.2.0.3.0
Thanks.Well, by default entire tables aren't stored in the buffer, just the blocks that were required. They are then aged out. You can view information on segment buffer pool usage here:
http://docs.oracle.com/cd/E11882_01/server.112/e16638/memory.htm#i40226
If you want to keep objects in memory, you can use the KEEP pool. It's generally not needed.

3750G won't "age out" old arp table entries

Similar Messages

Maybe you are looking for