Ping At L3 3560

Unanswered Question
Jun 12th, 2007
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Dear Sir,

I have layer3 3560 switch, switch Ip

I have One Pc with ip & other Pc

Some times I can not get the ping of from

At that time if ping its gateway means 192,168.1.1 , its gets reply , an then

Started reply from

Why it was occur I can not understand. Help Me.

Thanking You

Dipak Parmar

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Overall Rating: 4 (1 ratings)
smothuku Tue, 06/12/2007 - 03:34
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Have you configured default gateway on both pc's.



mtechnology Tue, 06/12/2007 - 03:46
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Does the pcs connected to same switch or different,

if in same switch check the port setting (speed& duplex).

have you seek with any other Pc like IP in the same subnet,

if pcs in different switch during the problem time try ping with different Pc, and check in the uplink port any errors.

dipak-parmar Tue, 06/12/2007 - 04:10
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they both are on same switch

i checked speed & Duplex

if i check ping for other pc i do not get

reply at that time

thanking you

smothuku Tue, 06/12/2007 - 04:39
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Hi Dipak ,

can you paste the config of the switch .....



guruprasadr Tue, 06/12/2007 - 03:39
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HI Dipak,

Can you please check the "Netmask" configured is same for Switch IP, PC1 & PC2.

Check the Default Gateway of the PC's.

See the Port Status to which PC1 & PC2 connected. Try to do some extended Ping from Switch.

Check whether the ports are in Forwarding / Blocking State.

Do multiple ping from different Src - to - destn.. & see the status of the Switch Int...

PLS Rate if Helps

Best Regards,

Guru Prasad R

dipak-parmar Tue, 06/12/2007 - 21:07
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subnet mask of switch ip Pc1,Pc2 is

both pc defalt gateway

port status up

Timor_SSS Wed, 06/13/2007 - 01:45
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Try to see logs (show loggin), see if there are any changes on port status when the problem accures.

Check you arp table on the switch, see if you're able to see both Pc's on arp on the same Vlan. Check you arp table on the Pc's as well. i suspect you have some sort of ARP issue on on of your servers or the switch.

If you'll post the running-config, it might help finding the problem more rapidly.



dipak-parmar Wed, 06/13/2007 - 02:24
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Thanks TIMor,

I have same suspects ,

how I increase my arp cache , & rapid

Refresh rate to sort this arp issue

I am sending my configuration

at Switch


version 12.2

no service pad

service timestamps debug uptime

service timestamps log datetime localtime

no service password-encryption


ip subnet-zero

ip routing

no ip domain-lookup





no errdisable detect cause pagp-flap

no errdisable detect cause dtp-flap

no errdisable detect cause link-flap

no errdisable detect cause l2ptguard

no errdisable detect cause sfp-config-mismatch

no errdisable detect cause gbic-invalid

no errdisable detect cause dhcp-rate-limit

no errdisable detect cause arp-inspection

no errdisable detect cause loopback

no file verify auto


spanning-tree mode pvst

spanning-tree logging

spanning-tree extend system-id

no spanning-tree vlan 2,6


vlan internal allocation policy ascending



interface GigabitEthernet0/1

description "PC2"

switchport access vlan 6

switchport mode access

speed 1000

duplex full


interface GigabitEthernet0/2

description "PC1"

switchport access vlan 6

switchport mode access

speed 1000

duplex full

interface Vlan6

description "Third Floor LAN"

ip address


ip classless

smothuku Wed, 06/13/2007 - 03:24
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Hi ,

set the speed and duplex on g0/1 and g0/2 of switch to "auto" and check the issue.



ahmet-saat Wed, 06/13/2007 - 02:06
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Hi Dipak,

Are u using 3560 as Layer3 or Layer2. I mean if you have vlans, you can check that the PCs are on same VLAN.

Pls rate if it helps..

mathew.webb Wed, 06/13/2007 - 06:05
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Try putting the switch ports into a portfast mode and see if you can ping.


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