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Hi! Today, I tested STP with my two switches by simply connecting them with two cables. As shown below, one of the links belonging to the non-root bridge got blocked based on the priority number. pi#show spanning-tree vlan 1 VLAN0001 Spanning tree enabled protocol ieee Root ID Priority 32769 Address ec30.918e.c100 Cost 19 Port 5 (FastEthernet0/3) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32769 (priority 32768 sys-id-ext 1) Address f029.2952.8d80 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 300 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Fa0/1 Desg FWD 19 128.3 P2p Fa0/3 Root FWD 19 128.5 P2p Fa0/5 Altn BLK 19 128.7 P2p As the above shows, Fa0/3 is the root port connected to the switch on the other end. So I plugged it out to see if the connection remains up by changing the root port to Fa0/5. Below is the result. pi>show spanning-tree vlan 1 VLAN0001 Spanning tree enabled protocol ieee Root ID Priority 32769 Address ec30.918e.c100 Cost 19 Port 7 (FastEthernet0/5) Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Bridge ID Priority 32769 (priority 32768 sys-id-ext 1) Address f029.2952.8d80 Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec Aging Time 15 sec Interface Role Sts Cost Prio.Nbr Type ------------------- ---- --- --------- -------- -------------------------------- Fa0/1 Desg FWD 19 128.3 P2p Fa0/5 Root LIS 19 128.7 P2p As expected, Fa0/5 is now the root port and the connection is still up! However, one drawback of this configuration is that one of the links is left unused. In order to utilize both of the links, I can set up an etherchannel and bundle the two links. I'm currently studying etherchannel to actually test it out and see how it differs from simply connected redundant links🧐.

Hi! Today, I was working on Inter VLAN Routing using a router(800) and L2 switch(Catalyst 2960). I connected a PC to each VLAN(VLAN10, VLAN20) and tested if I can ping to each other. Below is the set up for the PCs(Windows, Raspberry Pi) connected to the switch. The ip address for the Windows PC is 192.168.1.2/24 and the gateway address for 192.168.2.0/24 is 192.168.1.1/24. For Raspberry Pi, its ip address is 192.168.2.2/24 and the gateway address for 192.168.1.0/24 is 192.168.2.1/24. C:\WINDOWS\system32>route add 192.168.2.0 mask 255.255.255.0 192.168.1.1 OK! ┌──(kali㉿kali-raspberry-pi)-[~] └─$ sudo ifconfig eth0 192.168.2.2 ┌──(kali㉿kali-raspberry-pi)-[~] └─$ sudo ip route add 192.168.1.0/255.255.255.0 via 192.168.2.1 dev eth0 onlink ┌──(kali㉿kali-raspberry-pi)-[~] └─$ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.164.146 0.0.0.0 UG 600 0 0 wlan0 192.168.1.0 192.168.2.1 255.255.255.0 UG 0 0 0 eth0 192.168.2.0 192.168.2.1 255.255.255.0 UG 0 0 0 eth0 192.168.164.0 0.0.0.0 255.255.255.0 U 600 0 0 wlan0 Then I configured the switch. I prepared vlan10 & vlan20 for the Windows PC & Raspberry Pi, respectively. After finishing setting up vlans, you need to assign ports to the respective vlans. This time, I used 4 cables, two for connecting the PCs to the switch and the other two for connecting the router. Here are the commands I used for creating vlans. Switch>enable Switch#config terminal Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#vlan 10 Switch(config-vlan)#vlan 20 Switch(config-vlan)#do show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4 Fa0/5, Fa0/6, Fa0/7, Fa0/8 Fa0/9, Fa0/10, Fa0/11, Fa0/12 Fa0/13, Fa0/14, Fa0/15, Fa0/16 Fa0/17, Fa0/18, Fa0/19, Fa0/20 Fa0/21, Fa0/22, Fa0/23, Fa0/24 Gi0/1, Gi0/2 10 VLAN0010 active 20 VLAN0020 active 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup Next I assigned the ports to the respective vlans. Switch(config)#do show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4 Fa0/5, Fa0/6, Fa0/7, Fa0/8 Fa0/9, Fa0/10, Fa0/11, Fa0/12 Fa0/13, Fa0/14, Fa0/15, Fa0/16 Fa0/17, Fa0/18, Fa0/19, Fa0/20 Fa0/21, Fa0/22, Fa0/23, Fa0/24 Gi0/1, Gi0/2 10 VLAN0010 active 20 VLAN0020 active 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 0 0 10 enet 100010 1500 - - - - - 0 0 20 enet 100020 1500 - - - - - 0 0 1002 fddi 101002 1500 - - - - - 0 0 Switch(config)#interface fa0/1 Switch(config-if)# 00:02:41: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/3 (1), with Router FastEthernet0 (10). Switch(config-if)# 00:02:47: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/5 (1), with Router FastEthernet1 (20). Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 10 Switch(config-if)#interface fa0/2 Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 20 Switch(config-if)# 00:03:36: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/3 (1), with Router FastEthernet0 (10). Switch(config-if)#interface fa0/3 Switch(config-if)#switchport access vlan 20 00:03:42: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/5 (1), with Router FastEthernet1 (20). Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 10 Switch(config-if)#interface fa0/5 Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 20 Switch(config-if)#switchport access vlan 20 00:04:10: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state tmode access Switch(config-if)#do show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/4, Fa0/6, Fa0/7, Fa0/8 Fa0/9, Fa0/10, Fa0/11, Fa0/12 Fa0/13, Fa0/14, Fa0/15, Fa0/16 Fa0/17, Fa0/18, Fa0/19, Fa0/20 Fa0/21, Fa0/22, Fa0/23, Fa0/24 Gi0/1, Gi0/2 10 VLAN0010 active Fa0/1, Fa0/3 20 VLAN0020 active Fa0/2, Fa0/5 1002 fddi-default act/unsup 1003 token-ring-default act/unsup 1004 fddinet-default act/unsup 1005 trnet-default act/unsup VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2 ---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 1 enet 100001 1500 - - - - - 0 0 10 enet 100010 1500 - - - - - 0 0 20 enet 100020 1500 - - - - - 0 0 1002 fddi 101002 1500 - - - - - 0 0 1003 tr 101003 1500 - - - - - 0 0 After working on the switch, I had to configure the ports on the router each connected to the switch's vlan port. At first, I tried to assign IP address to the ports directly but I got this error. Router#config terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#interface fastethernet0 Router(config-if)#ip address 192.168.1.1 255.255.255.0 % IP addresses may not be configured on L2 links. The problem was that the port which I was configuring only works with L2 layer and an IP address can't be assigned. After doing some research, I figured out that I need to first create a vlan so that I can assign an IP address to it. The created vlan with an IP address can then be assigned to a port of your choice. Here is how I did it. Router(config)#vlan 10 Router(config-vlan)#vlan 20 Router(config-vlan)#interface vlan 10 Router(config-if)#ip address 192.168.1.1 255.255.255.0 % 192.168.1.0 overlaps with Vlan1 Router(config-if)#interface vlan 1 Router(config-if)#ip address 192.168.3.1 255.255.255.0 Router(config-if)#interface vlan 10 Router(config-if)#ip address 192.168.1.1 255.255.255.0 Router(config-if)#no shut Router(config-if)#interface vlan 20 Router(config-if)# *Jan 3 09:40:49.434: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan20, changed state to down Router(config-if)#ip address 192.168.2.1 255.255.255.0 % 192.168.2.0 overlaps with Vlan2 Router(config-if)#interface vlan 2 Router(config-if)#ip address 192.168.4.1 255.255.255.0 Router(config-if)#interface vlan 20 Router(config-if)#ip address 192.168.2.1 255.255.255.0 Router(config-if)#no shut Router(config-if)#interface fastethernet 1 Router(config-if)#switchport access vlan 10 Router(config-if)#interface fastethernet 2 Router(config-if)#switchport access vlan 20 Router(config-if)#exit Router(config)# Router(config)#do show interface (| include Vlan) ... Vlan10 is up, line protocol is up Hardware is EtherSVI, address is e4d3.f166.3fd2 (bia e4d3.f166.3fd2) Internet address is 192.168.1.1/24 MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 ... Vlan20 is up, line protocol is up Hardware is EtherSVI, address is e4d3.f166.3fd2 (bia e4d3.f166.3fd2) Internet address is 192.168.2.1/24 MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec, reliability 255/255, txload 1/255, rxload 1/255 ... Below is the routing table after configuring the router. Router>show ip route Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP + - replicated route, % - next hop override Gateway of last resort is not set 192.168.1.0/24 is variably subnetted, 2 subnets, 2 masks C 192.168.1.0/24 is directly connected, Vlan10 L 192.168.1.1/32 is directly connected, Vlan10 192.168.2.0/24 is variably subnetted, 2 subnets, 2 masks C 192.168.2.0/24 is directly connected, Vlan20 L 192.168.2.1/32 is directly connected, Vlan20 Now we are ready to ping the PC on the other VLAN connected by the router! Here is the result pinging from the Windows PC(192.168.1.2/24) to Raspberry Pi(192.168.2.2/24) C:\Users\Ryo>ping 192.168.2.2 Pinging 192.168.2.2 with 32 bytes of data: Reply from 192.168.2.2: bytes=32 time=1ms TTL=63 Reply from 192.168.2.2: bytes=32 time=11ms TTL=63 Reply from 192.168.2.2: bytes=32 time=1ms TTL=63 Reply from 192.168.2.2: bytes=32 time=1ms TTL=63 Ping statistics for 192.168.2.2: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 1ms, Maximum = 11ms, Average = 3ms Configuring the router was somewhat difficult as the commands I found online for inter VLAN routing didn't work for the router(800). I had to do some researching to find the commands that works for the router but it was fun as you don't get to do this kind of researching when you are working on packet tracer😎.

I tried to understand the difference between VLAN and subnet by looking into their ARP broadcast request. First I deleted all the ARP entries on the source PC so that when I ping, there will be an ARP request broadcasted to all the devices connected to the switch. Here is how you can check and delete the ARP table. C:\>arp -a Internet Address Physical Address Type 192.168.2.4 0001.436a.8be5 dynamic C:\>arp -d C:\>arp -a No ARP Entries Found After deleting all the ARP entries, the source PC will send an ARP request as it has no mac address on its table. Here is the list of ports on the switch when an ARP request was sent. It shows an ARP reqeust is sent to all the ports except the one(FastEthernet0/3) which is connected to the source PC. In addition, even though FastEthernet0/1-2 are not within the same subnet(192.168.2.0/24), you can see that they still receive the ARP request sent by the source PC(192.168.2.2/24). 1. FastEthernet0/1 sends out the frame. #192.168.1.2 2. FastEthernet0/2 sends out the frame. #192.168.1.3 3. FastEthernet0/4 sends out the frame. #192.168.2.3 4. FastEthernet0/5 sends out the frame. #192.168.2.4 Now its time see how an ARP request will behave when the switch is divided into VLANs(192.168.1.0/24, 192.168.2.0/24) . I once again deleted all the ARP entries in the table of the source PC and here is the commands I used for creating VLANs. Switch>enable Switch#config terminal Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#int fa0/1 Switch(config-if)#exit Switch(config)#vlan 10 Switch(config-vlan)#vlan 20 Switch(config-vlan)#int fa0/1 Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 10 Switch(config-if)#int fa0/2 Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 10 Switch(config-if)#int fa0/3 Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 20 Switch(config-if)#int fa0/4 Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 20 Switch(config-if)#int fa0/5 Switch(config-if)#switchport mode access Switch(config-if)#switchport access vlan 20 Switch(config-if)#do show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/6, Fa0/7, Fa0/8, Fa0/9 Fa0/10, Fa0/11, Fa0/12, Fa0/13 Fa0/14, Fa0/15, Fa0/16, Fa0/17 Fa0/18, Fa0/19, Fa0/20, Fa0/21 Fa0/22, Fa0/23, Fa0/24, Gig0/1 Gig0/2 10 vlan01 active Fa0/1, Fa0/2 20 vlan02 active Fa0/3, Fa0/4, Fa0/5 1002 fddi-default active 1003 token-ring-default active 1004 fddinet-default active 1005 trnet-default active I created VLAN01 and VLAN02 for 192.168.1.0/24 and 192.168.2.0/24, respectively. And here is the list of the ports that received an ARP request sent by the source PC(192.168.2.2/24). It shows that FastEthernet0/1-2 are not receiving an ARP request any more as they no longer belong to the same VLAN as the source PC(VLAN02)! 1. FastEthernet0/4 sends out the frame. #VLAN01 2. FastEthernet0/5 sends out the frame. #VLAN02 Once you are done with the VLANs, you can place the ports back to the default VLAN by the below commands. Switch(config-if-range)#interface range Fa 0/1-5 Switch(config-if-range)#switchport access vlan 1 Switch(config-if-range)#do show vlan VLAN Name Status Ports ---- -------------------------------- --------- ------------------------------- 1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4 Fa0/5, Fa0/6, Fa0/7, Fa0/8 Fa0/9, Fa0/10, Fa0/11, Fa0/12 Fa0/13, Fa0/14, Fa0/15, Fa0/16 Fa0/17, Fa0/18, Fa0/19, Fa0/20 Fa0/21, Fa0/22, Fa0/23, Fa0/24 Gig0/1, Gig0/2 10 vlan01 active 20 vlan02 active 1002 fddi-default active 1003 token-ring-default active 1004 fddinet-default active 1005 trnet-default active Switch(config-if-range)#no vlan 10 Switch(config-if-range)#no vlan 20

After studying how different devices work at different layers, I got little confused how ping works if its only given ip address to reach the destination pc connected via switch which is a layer 2 device. Here's how it works. 1. We only have the destination's ip and no mac address info. ->ARP request which is broadcasted to all devices connected to the switch. 2. Once your PC has the mac address in its mac address table, the frame is sent to the switch which contains the mac address of the destination pc. 3. Switch needs to know which port is connected to the PC with the destination mac address. ->Flood the frame to all other ports if the destination mac address is not in the mac address table. 4. Once the switch gets the reply form the destination PC, it now knows which port to send the frame to get to the destination PC! Here are ARP and Mac address tables before and after ping. Switch#show mac address-table Mac Address Table ------------------------------------------- Vlan Mac Address Type Ports ---- ----------- -------- ----- Switch#show mac address-table Mac Address Table ------------------------------------------- Vlan Mac Address Type Ports ---- ----------- -------- ----- 1 00e0.8fe3.e0b3 DYNAMIC Fa0/2 1 00e0.f7a1.365d DYNAMIC Fa0/1 C:\>arp -a No ARP Entries Found C:\>arp -a Internet Address Physical Address Type 192.168.1.2 00e0.8fe3.e0b3 dynamic

For testing static routes, I created a system with 2 routers each connected to a PC. There are 3 networks so that one PC can connect to the other after setting up a static route. Here I first configured router's interface for 192.168.1.0/24 and 192.168.1.1/24 is the default gateway for 192.168.1.0/24. I did the same for the other router responsible for 192.168.2.0/24. The third network(192.168.3.0/24) which needs to be configured is the one connecting the two routers. Router>enable Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#interface GigabitEthernet 0/0/0 Router(config-if)#ip address 192.168.1.1 255.255.255.0 Router(config-if)#no shutdown Router(config-if)# %LINK-5-CHANGED: Interface GigabitEthernet0/0/0, changed state to up %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0/0, changed state to up Router(config-if)#do show interfaces GigabitEthernet0/0/0 is up, line protocol is up (connected) Hardware is ISR4331-3x1GE, address is 0001.4384.9c01 (bia 0001.4384.9c01) Internet address is 192.168.1.1/24 ... After setting up all three networks, I pinged form the PC with 192.168.1.2/24. But the result shows that it is still not reachable. C:\>ping 192.168.2.2 Pinging 192.168.2.2 with 32 bytes of data: Reply from 192.168.1.1: Destination host unreachable. Reply from 192.168.1.1: Destination host unreachable. Reply from 192.168.1.1: Destination host unreachable. Reply from 192.168.1.1: Destination host unreachable. Ping statistics for 192.168.2.2: Packets: Sent = 4, Received = 0, Lost = 4 (100% loss), The remaining task is to set up the static routes so that the packet can reach the PC with 192.168.2.2/24. Here is how I set up the static route for 192.168.2.2/24. Router(config)#ip route 192.168.2.0 255.255.255.0 192.168.3.2 After setting up as above, you still won't be able to get replies from the other end as the returning packets get lost at the 192.168.3.2/24. C:\>ping 192.168.2.2 Pinging 192.168.2.2 with 32 bytes of data: Request timed out. Request timed out. Request timed out. Request timed out. Ping statistics for 192.168.2.2: Packets: Sent = 4, Received = 0, Lost = 4 (100% loss), Once I set up the static route as below, I was able to get replies from 192.168.2.2/24! Router(config)#ip route 192.168.1.0 255.255.255.0 192.168.3.1 C:\>ping 192.168.2.2 Pinging 192.168.2.2 with 32 bytes of data: Reply from 192.168.2.2: bytes=32 time<1ms TTL=126 Reply from 192.168.2.2: bytes=32 time=10ms TTL=126 Reply from 192.168.2.2: bytes=32 time<1ms TTL=126 Reply from 192.168.2.2: bytes=32 time=11ms TTL=126 Ping statistics for 192.168.2.2: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 11ms, Average = 5ms

I have been studying basic networking by reading books for CCNA. At this point, I think I should go hands-on with packet tracer or the router (Cisco 892) and switches (Cisco L2 and L3) I bought this week for studying purpose. Here are the list of the things I want to try hands-on. ・Static route ・OSPF ・ACL ・DHCP ・Unidirection & Bidirectional NAT ・NAPT(PAT) ・VLAN only using access ports (single switch) ・VLAN using access and trunk ports (two switches) ・VLAN rounting (using router and L2 switch, later using L3 switch)

I started using packet tracer and enjoying the tool a lot. I configured hub, switch, and router based network using the tool. It's really fun to put the materials you learned from books into practice! Here are the commands I used for configuring the router and the details of what it's doing. Router>enable Router# Router#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)#interface GigabitEthernet0/0 #select the port(interface) on the router Router(config-if)#ip address 192.168.1.4 255.255.255.0 #assign gateway IP address to the interface Router(config-if)#no shutdown #bring up the inerface Router(config-if)# %LINK-5-CHANGED: Interface GigabitEthernet0/0, changed state to up Here I tested if I am connected to the network configured above by pinging from a node within another network. C:\>ping 192.168.1.3 Pinging 192.168.1.3 with 32 bytes of data: Request timed out. Reply from 192.168.1.3: bytes=32 time=14ms TTL=127 Reply from 192.168.1.3: bytes=32 time<1ms TTL=127 Reply from 192.168.1.3: bytes=32 time=11ms TTL=127 Ping statistics for 192.168.1.3: Packets: Sent = 4, Received = 3, Lost = 1 (25% loss), Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 14ms, Average = 8ms It shows that the first packet is dropped. This is because of the switch on the network configured above does not have not have the destination pc's MAC address in its ARP table and need to get the one by 'flooding' which takes some time.

"ip addr" shows the mac address for each interface, it's e4:5f:01:d3:5b:da in the case of wlan0. "arp" shows the router's mac address. ┌──(kali㉿kali-raspberry-pi)-[/var/lib/dhcp] └─$ ip addr ... 3: wlan0: mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether e4:5f:01:d3:5b:da brd ff:ff:ff:ff:ff:ff inet 192.168.164.76/24 brd 192.168.164.255 scope global dynamic noprefixroute wlan0 valid_lft 2858sec preferred_lft 2858sec inet6 fe80::ed36:b7c6:afa8:838d/64 scope link noprefixroute valid_lft forever preferred_lft forever ┌──(kali㉿kali-raspberry-pi)-[/var/lib/dhcp] └─$ arp Address HWtype HWaddress Flags Mask Iface 192.168.164.146 ether ac:a8:8e:ec:6e:66 C wlan0 The first hop of "traceroute", which is 192.168.164.146, shows the router's local ip address. ┌──(kali㉿kali-raspberry-pi)-[~] └─$ traceroute 8.8.8.8 traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets 1 192.168.164.146 (192.168.164.146) 40.242 ms 41.001 ms 43.085 ms 2 121.83.171.60 (121.83.171.60) 74.412 ms 74.476 ms 76.689 ms 3 100.64.3.181 (100.64.3.181) 81.472 ms 81.503 ms 83.573 ms 4 58.191.128.178 (58.191.128.178) 86.298 ms 85.972 ms 86.346 ms 5 61.205.127.233 (61.205.127.233) 86.192 ms 87.454 ms 87.482 ms 6 203.140.81.209 (203.140.81.209) 86.012 ms 48.984 ms 55.241 ms 7 60.56.20.190 (60.56.20.190) 54.917 ms 54.165 ms 62.331 ms 8 142.250.172.36 (142.250.172.36) 62.152 ms 61.755 ms 65.046 ms 9 * * * 10 dns.google (8.8.8.8) 65.708 ms 65.737 ms 65.926 ms After piging to my laptop within the same local network, my laptop's mac address is added to the arp table. But ping is failing for some reason... ┌──(kali㉿kali-raspberry-pi)-[/var/lib/dhcp] └─$ ping 192.168.164.137 PING 192.168.164.137 (192.168.164.137) 56(84) bytes of data. ^C --- 192.168.164.137 ping statistics --- 7 packets transmitted, 0 received, 100% packet loss, time 6143ms ┌──(kali㉿kali-raspberry-pi)-[/var/lib/dhcp] └─$ arp Address HWtype HWaddress Flags Mask Iface 192.168.164.146 ether ac:a8:8e:ec:6e:66 C wlan0 192.168.164.137 ether 50:c2:e8:29:9b:cb C wlan0 Wireshark shows the arp protocol is requesting the mac address of 192.168.164.137, and the response from the router shows the mac address is 50:c2:e8:29:9b:cb. However there is no response from 192.168.164.76. 2 18.664379309 Raspberr_d3:5b:da Broadcast ARP 42 Who has 192.168.164.137? Tell 192.168.164.76 3 18.680115301 CloudNet_29:9b:cb Raspberr_d3:5b:da ARP 42 192.168.164.137 is at 50:c2:e8:29:9b:cb 4 18.680196856 192.168.164.76 192.168.164.137 ICMP 98 Echo (ping) request id=0x0002, seq=1/256, ttl=64 (no response found!) I checked my laptop's firewall configuration and enable ping echo request. Ping is now working! ┌──(kali㉿kali-raspberry-pi)-[~] └─$ ping 192.168.164.137 PING 192.168.164.137 (192.168.164.137) 56(84) bytes of data. 64 bytes from 192.168.164.137: icmp_seq=1 ttl=128 time=53.2 ms 64 bytes from 192.168.164.137: icmp_seq=2 ttl=128 time=75.9 ms 64 bytes from 192.168.164.137: icmp_seq=3 ttl=128 time=8.42 ms 64 bytes from 192.168.164.137: icmp_seq=4 ttl=128 time=42.1 ms 64 bytes from 192.168.164.137: icmp_seq=5 ttl=128 time=8.71 ms ^C --- 192.168.164.137 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4006ms rtt min/avg/max/mdev = 8.417/37.644/75.852/26.122 ms

I didn't know there are protocols defining the optimal path for exchanging packets between networks. It's interesting how they use different metrics(hop count, bandwidth, etc) to determine the best path.

I started studying for CCNA hoping to learn basic networking!