I am able to telnet into a switch, but I cannot ping it.

[mikecasciano53]

Hi.  I am having an issue where I am able to Telent into my stacked switch, but not ping it.  I am puzzled.  Does anyone have any idea why this could be happening?

[Brandon Svec]

Well, without any details anything would be a guess ;)

What type of switch?

Are you telneting from the same subnet as the switch admin interface?

A switch could have an ACL preventing ping and if you are routing to the switch some layer 3 device between you and the switch could prevent ping as well.

If you are not on the same subnet you may also be missing a return route from the switch, but if that was the case I suppose telnet would not work either.

[mikecasciano53]

I guess some details would help... :)

So I have 7 stacked Cisco SG500-x switches stacked via fiber.  The stack is setup into layer 3 mode.  I can pretty much ping everything else in my network.  I can't ping any of the VLANs in the switch either. 

I have my PC plugged in directly to port 12 right now.

I'm not sure about the switch admin interface, but i'll look into that.

We are on the same subnet.

It's used for video switching, and other then not being able to ping it everything seems to be working fine.

My running config is as followed (I removed some of it, because it follows a pretty simple pattern).

switch917c29#sh run
config-file-header
switch917c29
v1.3.0.62 / R750_NIK_1_3_647_260
CLI v1.0
set system queues-mode 4

file SSD indicator encrypted
@
ssd-control-start
ssd config
ssd file passphrase control unrestricted
no ssd file integrity control
ssd-control-end cb0a3fdb1f3a1af4e4430033719968c0
!
vlan database
vlan 5,53,100-184,230,250
exit
voice vlan oui-table add 0001e3 Siemens_AG_phone________
voice vlan oui-table add 00036b Cisco_phone_____________
voice vlan oui-table add 00096e Avaya___________________
voice vlan oui-table add 000fe2 H3C_Aolynk______________
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00e075 Polycom/Veritel_phone___
voice vlan oui-table add 00e0bb 3Com_phone______________
bonjour interface range vlan 1
hostname switch917c29
line telnet
exec-timeout 0
exit
clock timezone " " -4
clock source browser
ip telnet server
!
interface vlan 1
 no ip address dhcp
!
interface vlan 5
 name SIM
 ip address 10.50.1.254 255.255.0.0
!
interface vlan 100
 ip address 10.100.100.1 255.255.255.0
!
interface vlan 101
 ip address 10.100.101.1 255.255.255.0
!
interface vlan 102
 ip address 10.100.102.1 255.255.255.0
!
interface vlan 103
 ip address 10.100.103.1 255.255.255.0

.

.

!
interface vlan 183
 ip address 10.100.183.1 255.255.255.0
!
interface vlan 184
 ip address 10.100.184.1 255.255.255.0
!
interface vlan 250
 name BLANK
 ip address 10.100.250.1 255.255.255.0
!
interface gigabitethernet1/1/1
 spanning-tree portfast
 switchport mode general
 switchport general allowed vlan add 100-101 untagged
 switchport general pvid 101
!
interface gigabitethernet1/1/2
 spanning-tree portfast
 switchport mode general
 switchport general allowed vlan add 100,102 untagged
 switchport general pvid 102
!
interface gigabitethernet1/1/3
 spanning-tree portfast
 switchport mode general
 switchport general allowed vlan add 100,103 untagged
 switchport general pvid 103
!

.

interface gigabitethernet1/1/11
 spanning-tree portfast
 switchport mode general
 switchport general allowed vlan add 100,111 untagged
 switchport general pvid 111
!
interface gigabitethernet1/1/12
 spanning-tree portfast
 switchport mode access
 switchport access vlan 5
!

.

.

!
interface gigabitethernet7/1/23
 spanning-tree portfast
 switchport mode general
 switchport general allowed vlan add 100,250 untagged
 switchport general pvid 100
!
interface gigabitethernet7/1/24
 spanning-tree portfast
 switchport mode general
 switchport general allowed vlan add 100,250 untagged
 switchport general pvid 100
!
exit

[Brandon Svec]

It seems in port 12 you will have an IP in the range of 10.50.0.0/16 and then you telnet, but can't ping to what address?  Can you confirm the IP, subnet and gateway on your PC you are telneting from?

[mikecasciano53]

So the IP address of my PC is

Ethernet adapter SIM:

   Connection-specific DNS Suffix  . :
   IPv4 Address. . . . . . . . . . . : 10.50.20.20
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . : 10.50.1.254

The IP Address i'm trying to ping is:

interface vlan 5
 name SIM
 ip address 10.50.1.254 255.255.0.0
!

So yeah, we're in the same subnet.

[Brandon Svec]

You are indeed on the same subnet.  I think you also said you can ping other things so it rules out a software firewall on your PC?

So now we are both puzzled.

Maybe time to run wireshark if you are really interested to solve this?

[mikecasciano53]

Yeah, i've tried that too.  Looks like it's sending out the ICMP requests, nothing is being returned though.  Completely puzzled.

My initial though was maybe Cisco locked down ICMP for some type of security thing, but I can't find any settings that look like it would be blocking pings.

Hopefully at the end of the day it's just something silly, but who knows.

Thanks for helping!

[Aleksandra Dargiel]

Hi Mike,

I would recommend you to upgrade firmware and boot code first. It might save your time a bit.

Regards,

Aleksandra

[sushindms]

it works now.

thank you

I also like to know the reason behind the issue.

It occurs my SG300, SG500 series switches too.