can't ping from router to pc but pc to router can work (physical router)

mpate1311 · ‎03-10-2016

hello guys,

i was trying to connect physical router 1760 to pc via console. even though router and pc are in same network but ping is not working from router to pc but reverse can work . i already turned off the window firewall .

router f0/0 int ip= 172.31.1.62/24

pc ip =172.31.1.61/24

default getway=172.31.1.1

pc's cmd

C:\Users\mpatel>ping 172.31.1.62

Pinging 172.31.1.62 with 32 bytes of data:
Reply from 172.31.1.62: bytes=32 time=1ms TTL=64
Reply from 172.31.1.62: bytes=32 time<1ms TTL=64
Reply from 172.31.1.62: bytes=32 time<1ms TTL=64
Reply from 172.31.1.62: bytes=32 time<1ms TTL=64

Ping statistics for 172.31.1.62:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 1ms, Average = 0ms

C:\Users\mpatel>

the router cli

MISUFCAE01#ping 172.31.1.61

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.31.1.61, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)'

could you help me figure out this issue ?

thanks,

maulik

Cisco Freak · ‎03-10-2016

Please check if there is any software/configuration which denies inbound ICMP communication to the PC.

Also, please check if there is any ACL on the router interface which denies ICMP echo outbound.

CF

pwwiddicombe · ‎03-10-2016

Is there more to this network than the 2 devices (i.e. is there another live interface or loopback address on the router)?

What is the default gateway at 172.31.1.1?

Can you do another ping from the router specifying the source address as 172.31.1.62?

(to do this, just enter PING, then fill in when requested type IP, destination address of 172,31,1,61, and source address as 172.31.1.62.)

IF you have other interfaces configured, it's possible that the default source address from the router's ping is effectively unknown/not reachable from the PC.

mpate1311 · ‎03-11-2016

hello pwwiddicombe

thanks for your response !!

but there is no other than this two device and network. 172.31.1.1 is the default gateway of the pc and even tried ping including source address still it's not gonna work

# ping 172.31.1.61 source 172.31.1.62

even ping is not working !!

pwwiddicombe · ‎03-11-2016

On the PC, do you have wired AND wireless interfaces active at the same time? If so, try disabling the wireless - it may have a default route and be overriding the wired one facing the Cisco device.

Can you post the outputs of the following:

PC: Netstat -rn <- note that's r n, not m

Router:

sh ip route

sh ip int

PS: WHAT is the 172.31.1.1 default gateway from the PC, and WHY do you have it? In theory, it shouldn't be used as both devices are in the same subnet; but it can also create some confusion. Is it a static config; or WHAT is assigning that? Similarly, on the router, you shouldn't have a default route to a non-existing IP or device.

mpate1311 · ‎03-11-2016

IPv4 Route Table on PC
===========================================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 172.31.1.1 172.31.1.61 20
127.0.0.0 255.0.0.0 On-link 127.0.0.1 306
127.0.0.1 255.255.255.255 On-link 127.0.0.1 306
127.255.255.255 255.255.255.255 On-link 127.0.0.1 306
172.31.1.0 255.255.255.0 On-link 172.31.1.61 276
172.31.1.61 255.255.255.255 On-link 172.31.1.61 276
172.31.1.255 255.255.255.255 On-link 172.31.1.61 276
224.0.0.0 240.0.0.0 On-link 127.0.0.1 306
224.0.0.0 240.0.0.0 On-link 172.31.1.61 276
255.255.255.255 255.255.255.255 On-link 127.0.0.1 306
255.255.255.255 255.255.255.255 On-link 172.31.1.61 276
===========================================================================
Persistent Routes:
None

IPv6 Route Table
===========================================================================
Active Routes:
If Metric Network Destination Gateway
1 306 ::1/128 On-link
13 276 fe80::/64 On-link
13 276 fe80::c4a2:ed4a:5b78:3669/128
On-link
1 306 ff00::/8 On-link
13 276 ff00::/8 On-link
===========================================================================
Persistent Routes:
None

but i can not see any entry in router's route table

mpate1311 · ‎03-11-2016

i solved the problem i think access-list or any kind of outbound policy was trying to stop icmp echo so delete all the config then i tried it and it's gonna work now !

thank u so much !!