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Replies

Pingging with out default gateway

sathyasav
Level 1
Level 1

‎09-30-2011 08:34 AM - edited ‎03-07-2019 02:32 AM

Hi,

i have two switces at the site one is 4507 and another one is 3560 switch.4507 is configured as a core switch and 3560 switch configured as a access switch and vla 160 is a layer 3 vlan configured on both the switch and which providing connectivity between switches.

The ip address assigned to the core switch is 172.18.160.2 and eigrp is running betwen this switch and remote location.

The IP address assigned to the access switch is 172.18.160.6.

Here comes my question,i didnt configure any default route or any routing protol on the access switch,but still i am able to ping all the locations.How is it possible that the switch is pinging to outside address without any static,default route and routing protocol.

Please reply ASAP.

Thanks

Sathya

Labels:
0 Helpful
11 Replies 11

Reza Sharifi
Hall of Fame
Hall of Fame

‎09-30-2011 08:42 AM

Hi,

Do you have "ip default-gateway ip-address" configured on your access switch?

0 Helpful

Joseph W. Doherty
Hall of Fame
Hall of Fame

‎09-30-2011 09:38 AM

Disclaimer

The     Author of this posting offers the information  contained within this     posting without consideration and with the  reader's understanding   that   there's no implied or expressed suitability  or fitness for any    purpose.  Information provided is for informational  purposes only  and   should not  be construed as rendering professional  advice of any  kind.   Usage of  this posting's information is solely at  reader's own  risk.

Liability Disclaimer

In      no event shall Author be liable for any damages whatsoever    (including,   without limitation, damages for loss of use, data or    profit) arising  out  of the use or inability to use the posting's    information even if  Author  has been advised of the possibility of   such  damage.

Posting

Is the gateway interface for 172.18.160.6 supporting proxy ARP?

0 Helpful

sathyasav
Level 1
Level 1
In response to Joseph W. Doherty

‎09-30-2011 11:53 AM

Hi Reza,

i dont have any ip default-gateway address command configured.

Hi Joseph,

How to check that whether the gateway interface is supporting proxy ARP?and what is this proxy ARP.

0 Helpful

Reza Sharifi
Hall of Fame
Hall of Fame
In response to sathyasav

‎09-30-2011 12:00 PM

Hi,

Can you post "sh run" from the access switch?

0 Helpful

sathyasav
Level 1
Level 1
In response to Reza Sharifi

‎09-30-2011 12:08 PM

Please find the access switch config below.

ASB-BAN-SW55#sh run
Building configuration...

Current configuration : 11459 bytes
!
version 12.2
no service pad
service tcp-keepalives-in
service tcp-keepalives-out
service timestamps debug datetime msec localtime show-timezone
service timestamps log datetime msec localtime show-timezone
service password-encryption
service sequence-numbers
!
hostname ASB-BAN-SW55
!
logging buffered 16384 debugging
logging rate-limit 10 except critical
logging console critical
enable secret 5 $1$Ji3F$cxhrbDQnFzoDlzbSnU4C3.

!
no aaa new-model
vtp domain VELANKANISW1
vtp mode transparent
ip subnet-zero
no ip source-route
no ip gratuitous-arps
ip tcp synwait-time 20
no ip domain-lookup
ip domain-name ascorp.com
ip name-server 172.24.131.37
!
ip ssh authentication-retries 2
ip ssh source-interface Loopback0
ip ssh version 2
!
!
!
!
!
no file verify auto
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
vlan 160
name Server-Printer
!
vlan 164
name Data-VLAN-1stFLR
!
vlan 174
name Voice-VLAN-1stFLR
!
vlan 190
name Guest-New
!
!
interface Loopback0
ip address 172.31.254.116 255.255.255.255
no ip redirects
no ip proxy-arp
!
interface FastEthernet0/1
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/2
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/3
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/4
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/5
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/6
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/7
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/8
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/9
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/10
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/11
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/12
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/13
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/14
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/15
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/16
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/17
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/18
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/19
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/20
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/21
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/22
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/23
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/24
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/25
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/26
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/27
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/28
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/29
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/30
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/31
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/32
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/33
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/34
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/35
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/36
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/37
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/38
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/39
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/40
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/41
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/42
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/43
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/44
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/45
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/46
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/47
switchport access vlan 164
switchport mode access
switchport voice vlan 174
speed 100
duplex full
spanning-tree portfast
!
interface FastEthernet0/48
description #connectivity to ASB-BAN-SW51#PORT NO-GI7/48
switchport trunk encapsulation dot1q
switchport mode trunk
speed 100
duplex full
!
interface GigabitEthernet0/1
shutdown
!
interface GigabitEthernet0/2
shutdown
!
interface GigabitEthernet0/3
shutdown
!
interface GigabitEthernet0/4
shutdown
!
interface Vlan1
no ip address
shutdown
!
interface Vlan160
ip address 172.18.160.6 255.255.255.0
!
ip classless
no ip http server
no ip http secure-server
!
!
logging trap warnings
logging facility local2
logging source-interface Loopback0
logging 172.24.131.45
access-list 23 permit 172.18.44.0 0.0.0.255
access-list 23 permit 172.20.8.0 0.0.0.255
access-list 23 permit 172.31.254.0 0.0.0.255
access-list 24 permit 172.24.131.37
access-list 24 permit 172.24.131.45
access-list 24 permit 10.20.2.55
access-list 50 permit 172.24.128.117
access-list 50 permit 172.18.70.132
access-list 50 permit 172.20.8.14
access-list 50 permit 172.20.8.15
snmp-server trap-source Loopback0
snmp-server contact Network Management
snmp-server chassis-id
snmp-server enable traps snmp authentication linkdown linkup coldstart
snmp-server enable traps cluster
snmp-server enable traps entity
snmp-server enable traps vtp
snmp-server enable traps config
snmp-server enable traps hsrp
snmp-server enable traps bridge newroot topologychange
snmp-server enable traps vlan-membership
snmp-server host 172.24.128.117 OTXREAD
!
control-plane
!
banner motd ^CCCC

     ************************* WARNING ********************************
     *                                                                *
     * This computer  system is  private and  may be accessed only    *
     * by  authorized users.  Data  and  programs in  this  system    *
     * are  confidential and proprietary  to the  system owner and    *
     * may not be accessed, viewed, copied, reproduced, duplicated,   *
     * modifed,  distributed,  or disclosed without authorization.    *
     * Access to this system is logged and may be used as evidence    *
     * in court. Unauthorized users will be prosecuted to the full    *
     * extent of federal and state law,including criminal prosecution *
     * which may result in fines,imprisonment or both.                *
     *                                                                *
     *       If you are not authorized to use this system             *
     *                 YOU MUST EXIT IMMEDIATELY!                     *
     *                                                                *
     ******************************************************************


^C
!
line con 0
exec-timeout 5 0
password 7 04750E120226415A584B5653
login
line vty 0 4
session-timeout 10
exec-timeout 5 0
password 7 080F495A041E080343595F40
login
line vty 5 15
no login
!
scheduler interval 500
ntp clock-period 36028847
ntp source Loopback0
ntp access-group peer 24
ntp server 172.24.131.37
ntp server 172.24.131.45
ntp server 10.20.2.55
!
end

0 Helpful

Jonathancert_2
Level 1
Level 1
In response to sathyasav

‎09-30-2011 01:38 PM

The 4507 and the 3560 should be able to ping each becuase the are directly connected neighbors.   Are you saying you have other sites on different subnets that the 3560 can reach?

Jonathan,

0 Helpful

Joseph W. Doherty
Hall of Fame
Hall of Fame
In response to sathyasav

‎09-30-2011 05:21 PM

Disclaimer

The      Author of this posting offers the information  contained within  this     posting without consideration and with the  reader's  understanding   that   there's no implied or expressed suitability  or  fitness for any    purpose.  Information provided is for informational   purposes only  and   should not  be construed as rendering professional   advice of any  kind.   Usage of  this posting's information is solely  at  reader's own  risk.

Liability Disclaimer

In       no event shall Author be liable for any damages whatsoever     (including,   without limitation, damages for loss of use, data or     profit) arising  out  of the use or inability to use the posting's     information even if  Author  has been advised of the possibility of    such  damage.

Posting

sathyasav wrote:
Hi Joseph,
 How to check that whether the gateway interface is supporting proxy ARP?and what is this proxy ARP.

This will help explain:

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094adb.shtml

0 Helpful

sathyasav
Level 1
Level 1
In response to Joseph W. Doherty

‎10-04-2011 05:41 AM

So,if we enable proxy ARP on the core,default gateway is not required right to reach the outside world?

0 Helpful

Jon Marshall
Hall of Fame
Hall of Fame
In response to sathyasav

‎10-04-2011 05:51 AM

Yes, but the better solution is to configure a default-gateway on your L2 switches if you want to access them from remote subnets.

You should not rely on proxy-arp to do this. Basically your access switch arps for for every destination and relies on the core switch to work it out. If you configure a default-gateway on the switch then the switch simply needs arp to resolve the default-gateway IP address (+ any devices local to the switch management IP subnet).

Jon

0 Helpful

sathyasav
Level 1
Level 1
In response to Jon Marshall

‎10-04-2011 06:00 AM

Thanks Jon,

So it is always better to configure default gateway rather than depending on proxy ARP rite?

so eventhough we dont configure default gateway with the proxy ARP enabled,we can reach the outside subnets and viceversa.But it is always better to configure default gateway rather than depending on proxy ARP rite?

Jon please reply for this post.

SATHYA

0 Helpful

Richard Burts
Hall of Fame
Hall of Fame
In response to sathyasav

‎10-04-2011 08:19 AM

Sathya

Yes. Even though it can work using proxy arp, it is always better to configure a default gateway rather than depending on proxy arp.

HTH

Rick

HTH

Rick
0 Helpful
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