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Beginner

Unable To Ping From One PC to the Other PC

I have a simple physical network of one Windows 10 laptop, a 1921 Cisco router, a 1921 Cisco router, and another Windows 10 laptop.  Between the two routers is  a serial link, and fast ethernet links from the routers to the PCs.  Now, from the routers I can ping both PCs, but I am unable to ping from a Windows command prompt to the other PC (Request timed out).  Pinging from the Windows command prompt to the FE side of the router is no problem, but I am unable to ping the router's serial IP address. I have Windows Firewall and Anti-virus application disabled.  There doesn't seem to be an IP routing problem since I am able to ping from either router to the laptops.  I just can't seem to get past either FE connection and into the Serial connections from within Windows.  Oh, I am using crossover cables connecting laptops from USB ports to the routers FE ports.  Why can't Windows 10 see past the routers' FE ports?  Is there something I have to enable or disable?

17 REPLIES 17
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VIP Expert

Hello,

 

odd indeed. Can you post the configs of both routers ?

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Rising star

@kgndata21 ,

 

It looks like you haven't set the default gateway on the PCs, so they can ping the router which is directly attached to them, but can't ping any IP address outside of local segment. That explains why they can't even ping their local router's serial interface IP address. Basically they won't ping anything outside of their local segments, because they don't know how to get there. Set the default gateways and as long as routers do some dynamic routing or have static routes for each other's LAN networks, you should be good.

 

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VIP Expert

if you able to ping from Router to PC, so their respected routing domain ok.

if you are not able to ping PCA to PCB, so there is no routing take place.

 

this may be cause of below :

 

0. are you able to ping from PCA to Router Gateway ? ( can you post ipconfig /all from ) PCA and PCB)

1. router not routing

2. something blocking between routing domain

 

can you post config of the device.

also try tracert from PCA to PCB see where to stopped.

 



BB


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This is quite frustrating, to say the least. Here is some configuration data:

PC1- IP 192.168.101.2/24, DG 192.168.101.1

PC2-IP 192.168.100.2/24, DG 192.168.100.1

Router1 - F0/1/0 192.168.101.1/24, S0/0/0:0 192.168.1.1/24

Router2 - F0/1/0 192.168.100.1/24, S0/0/0:0 192.168.1.2/24

 

I have Windows firewall, anti-virus, and a VPN all turned off.  I am using a serial crossover cable between routers and a ethernet crossover cables between PCs and routers' FE interface.  I've enabled IP routing on both routers and issued the appropriate IP Route commands to establish static IP routes.  From the PCs I can ping the default gateways, but I cannot ping the serial interfaces.  What would prevent me from doing so?  Is there something unique about serial connections I am overlooking?  As I stated previously, I can ping from Router1 to PC2 and from Router2 to PC1, but I cannot ping from PC1 to PC2, not even, say, from PC1 to the serial side of Router1.  What is causing the blockage?  I need to try to make static routing work.  Thanks.

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Hello,

 

post the running configs of both routers. Are you using a serial DCE/DTE cable ? Does one side have clocking (clock rate command) ?

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Here's the thing, I have installed on the Cisco 1921 routers:  VWIC3-2MFT-T1/E1 - Cisco 2-Port T1/E1 Multiflex Trunk Voice/WAN Interface Cards.  I am also using a T1 crossover cable.  I thought maybe the problem has something to do with clock rate but I do not have access to a command for this.  Apparently clock rate is irrelevant in this case.  Any ideas? 

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try to enable debugging on the router and ping it from  the PC and see if you are getting any hits.

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Hello.  If you can, please take a look at my last reply to Georg.  I included my commands for the T1 controller on both routers plus my full configurations for both routers.  The thing is I can ping PC1 from the console port of router2, and I can ping PC2 from the the console port of router1.  I don't get it.  why can't PC1 ping PC2?

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Hello,

 

not sure if you mentioned the T1 crossover before, but that is the crucial piece of information. You need to configure the serial interfaces as below:

 

Side 1

 

service-module 56k clock source internal
service-module 56k network-type dds

 

Side 2

 

service-module 56k clock source line
service-module 56k network-type dds

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Thanks for that suggestion.  I'll give it a try later and let you know.

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Unfortunately, I receive an error msg when I try to enter the commands at either router.  

Error msg is 'Invalid input' beginning with the 56k parameter.  

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Hello,

 

what about:

 

service-module t1 clock source line
service-module t1 clock source internal

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No, same as before...when I did a service-module ? at the prompt, this is what resulted:  Embedded-Service-Engine cisco embedded service engine module

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Hello,

 

how did you configure the T1 controllers ? Post the full running configuration of both routers.