On GNS3 I have developed the following network:
The enp2s0f2 is my own computer network interface.
The router R1 configuration is shown below:
R1#show running-config Building configuration... Current configuration : 1077 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R1 ! boot-start-marker boot-end-marker ! ! no aaa new-model memory-size iomem 5 no ip icmp rate-limit unreachable ip cef ! ! no ip dhcp use vrf connected ! ip dhcp pool INTERNAL-CLIENT network 172.17.0.0 255.255.255.0 default-router 172.17.0.1 dns-server 1.1.1.1 ! ! ip name-server 1.1.1.1 ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ip tcp synwait-time 5 ! ! ! interface FastEthernet0/0 ip address dhcp ip nat outside duplex auto speed auto ! interface FastEthernet0/1 ip address 172.17.0.1 255.255.255.0 ip nat inside duplex auto speed auto ! ! ! no ip http server no ip http secure-server ip nat inside source list 1 interface FastEthernet0/0 overload ! access-list 1 permit 172.17.0.0 0.0.0.255 no cdp log mismatch duplex ! ! ! control-plane ! ! ! ! ! ! ! ! ! line con 0 exec-timeout 0 0 privilege level 15 logging synchronous line aux 0 exec-timeout 0 0 privilege level 15 logging synchronous line vty 0 4 login ! ! end R1#
On PC-1 I have:
PC-1> show ip all NAME IP/MASK GATEWAY MAC DNS PC-1 172.17.0.2/24 172.17.0.1 00:50:79:66:68:00 1.1.1.1
On router R1, I have:
R1#show ip interface brief Interface IP-Address OK? Method Status Protocol FastEthernet0/0 192.168.10.166 YES DHCP up up FastEthernet0/1 172.17.0.1 YES NVRAM up up NVI0 unassigned NO unset up up R1#
On my physical computer I have:
$ ip address
1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp2s0f2: mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether 70:4d:7b:3a:6e:2c brd ff:ff:ff:ff:ff:ff
inet 192.168.10.231/16 brd 192.168.255.255 scope global dynamic enp2s0f2
valid_lft 343522sec preferred_lft 343522sec
inet6 fe80::f39e:90d0:970:b350/64 scope link
valid_lft forever preferred_lft forever
3: wlp3s0: mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether 94:e9:79:2a:34:23 brd ff:ff:ff:ff:ff:ff
The point which I don't understand is that, on PC1, I can ping the google.com, 192.168.10.254 (gateway of my physical network) and 192.168.10.166 (IP of R1 interface), however I can NOT ping the 192.168.10.231 which is the IP of my physical computer which has the interface enp2s0f2, like below:
PC-1> ping google.com google.com resolved to 172.217.21.238 84 bytes from 172.217.21.238 icmp_seq=1 ttl=46 time=211.381 ms 84 bytes from 172.217.21.238 icmp_seq=2 ttl=46 time=151.149 ms 84 bytes from 172.217.21.238 icmp_seq=3 ttl=46 time=139.226 ms 84 bytes from 172.217.21.238 icmp_seq=4 ttl=46 time=171.411 ms 84 bytes from 172.217.21.238 icmp_seq=5 ttl=46 time=201.004 ms PC-1> ping 192.168.10.254 84 bytes from 192.168.10.254 icmp_seq=1 ttl=63 time=14.656 ms 84 bytes from 192.168.10.254 icmp_seq=2 ttl=63 time=29.997 ms 84 bytes from 192.168.10.254 icmp_seq=3 ttl=63 time=23.611 ms 84 bytes from 192.168.10.254 icmp_seq=4 ttl=63 time=29.338 ms 84 bytes from 192.168.10.254 icmp_seq=5 ttl=63 time=29.783 ms PC-1> ping 192.168.10.166 84 bytes from 192.168.10.166 icmp_seq=1 ttl=255 time=2.785 ms 84 bytes from 192.168.10.166 icmp_seq=2 ttl=255 time=9.686 ms 84 bytes from 192.168.10.166 icmp_seq=3 ttl=255 time=10.499 ms 84 bytes from 192.168.10.166 icmp_seq=4 ttl=255 time=9.364 ms 84 bytes from 192.168.10.166 icmp_seq=5 ttl=255 time=11.252 ms PC-1> ping 192.168.10.231 192.168.10.231 icmp_seq=1 timeout 192.168.10.231 icmp_seq=2 timeout 192.168.10.231 icmp_seq=3 timeout 192.168.10.231 icmp_seq=4 timeout 192.168.10.231 icmp_seq=5 timeout PC-1>
I couldn't understand why I cannot ping my physical computer from within the virtual PC-1 inside GNS3. Also, I cannot ping the router R1 interface from within the physical computer:
$ ping 192.168.10.166 PING 192.168.10.166 (192.168.10.166) 56(84) bytes of data. From 192.168.10.231 icmp_seq=1 Destination Host Unreachable From 192.168.10.231 icmp_seq=2 Destination Host Unreachable From 192.168.10.231 icmp_seq=3 Destination Host Unreachable From 192.168.10.231 icmp_seq=4 Destination Host Unreachable From 192.168.10.231 icmp_seq=5 Destination Host Unreachable From 192.168.10.231 icmp_seq=6 Destination Host Unreachable
Here is my routing table on the physical computer:
$ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.10.254 0.0.0.0 UG 20100 0 0 enp2s0f2 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 enp2s0f2 192.168.0.0 0.0.0.0 255.255.0.0 U 100 0 0 enp2s0f2
Best Answer
Since you can ping PC-1 from the physical PC (PH) but not vice versa, the most logical explanation is that PH doesn't reply to echo requests (firewall, filtering, ...).
Edit after your added PH's routing table:
On PH, you need to add a route
172.17.0.0/24->192.168.10.166. Otherwise the default gateway192.168.10.254is used, leading somewhere completely else...