7

On the switch, your IP for interface vlan 20 is wrong. # interface vlan 20 # ip address 10.1.2.1 255.255.255.0 # no shutdown Then make sure you have ip routing on. Also the gateway for PC A should be 10.1.1.1 while the gateway for PC B should be 10.1.2.1. The subnet mask should be 255.255.255.0 not the gateway. Once fixed, make sure you can ping the ...


6

You have the 10.0.0.0/8 and 172.16.0.0/16 networks defined on both the middle and right routers. Using auto-summary on both makes each think they own those whole summarized networks, so they will not send any traffic in those networks toward the other router. Using no auto-summary will allow each router to understand the more specific routes of each router.


6

A host knows if the destination address is on a different network (the same way that you do, by masking the host and destination addresses with the host mask). If the destination is on the same network, then it will send the layer-3 packet in a layer-2 frame directly to the destination, otherwise it will send the layer-3 packet in a layer-2 frame directly to ...


6

Serial ports don't have or need MAC addresses. It's as simple as that.


6

It's giving you that/those error(s) because removing that object would leave the access-list empty but still existing, which is not possible or allowed, and you can't delete an access-list like that (by just saying "no" on its only line). What you need to do is: clear config access-list out2in This will disassociate the access-list with the interface and ...


5

The loopback interface is useful because it is an interface with an IP address which never goes down. OSPF, without a specifically defined Router ID, will pick a Router ID on its own. It chooses the Router ID from the IP addresses of the configured and enabled interfaces. A loopback is a good choice since the loopback interface is always up unless someone ...


5

Dual stack means that an interface can communicate with both v4 and v6 clients. It DOES NOT mean that it will translate between the two. For that, you need to implement NAT-PT, to translate between the different layer 3 protocols. BTW, I've never seen NAT-PT work at any scale.


5

The easy part: Use Wireshark for the sniffing. The hard part: In a switched network you need support from the switch to get all the traffic. It is called "port mirroring", "span port", "monitor port" depending on the vendor. Without control over the switch you will not be able to capture all traffic.


5

The message you got is perfectly normal. That is not OSPF crashing, but it is telling you that the neighbor is no longer there. The interface is down, so OSPF cannot communicate with that neighbor. When an interface is down, the network attached to it no longer exists for OSPF, and it cannot exchange hellos with any neighbor through that interface.


5

1. The first issue is that you configured same Router-ID (RID) router-id 1.1.1.1 for R1 and R2 in area 45. All OSPF router should have different RIDs across the OSPF network domain. 2. And the reason PC1 cannot reach ABR (and other OSPF routers in the network also cannot reach the IPv4 and IPv6 addresses of R1's g0/0 interface) is that you did not enable ...


5

You can't have more than one access list per direction on an interface. So, to accomplish this, you will have to create a unique access-list for each interface that allows only the traffic you want.


5

The most common commands are show interfaces show ip interface brief Or for a specific interface show interfaces vlan 1


5

One side of the link (DCE), has to transmit the clock signal, which controls the data rate, and the other side (DTE) receives the clock signal. R1 is DCE here: interface Serial0/0/0 ip address 10.0.0.1 255.255.255.252 clock rate 2000000 R2 is DTE here: interface Serial0/0/0 ip address 10.0.0.2 255.255.255.252 The difference between the two cables in ...


5

R2's default route points back to R1. Instead it needs to point to R3 via Serial0/0/1.


5

MAC Addresses are specific to Ethernet interfaces - serial interfaces are point-to-point and use a different Layer 2 protocol (PPP, HDLC, FR etc.) for communication. EUI-64 is most likely deriving it's address from another source on your router.


5

Because you have not a star-shaped network, you have to define a route to reach each network. Your routes can be : 192.168.2.0/24 via 192.168.1.254 Default via 192.168.1.253 or 192.168.2.0/24 via 192.168.1.254 10.0.1.0/30 via 192.168.1.253 192.168.3.0/24 via 192.168.1.253 or Default via 192.168.1.254 10.0.1.0/30 via 192.168.1.253 192.168.3.0/24 via 192....


5

The mask you were trying to use really is a bad mask. You were trying to use 255.255.225.248. You simply had a typographical error that you eventually corrected. It happens, and it is a big reason to have a peer review of your work before putting it into production.


4

In addition to Gerben answer: IPv4 and IPv6 are to different protocols. So a IPv4 only client can only communicate with an IPv4 server. An IPv6 only client can only communicate with an IPv6 Server. Dual-Stacking means that you uses both protocols. Most modern operating systems will then prefer IPv6 over IPv4. There are some ways to "translate" one ...


4

In a dual stack network, a host has both an IPv4 and an IPv6 configuration allowing them to choose which protocol to use. When communicating with an IPv6 host, it will use its IPv6 address, when talking to an IPv4 host, it will use its IPv4 address. From your question, I gather that you have IPv4 on all systems, but IPv6 is only configured on the routers. ...


4

First, loopbacks interfaces are mainly used when we want to establish adjacencies between 2 equipments (i.e. routers) and to be sure that when one link fails, the adjacency will not go down because, loopbacks interfaces are logical interfaces, and you can reach them by different ways. Another use for this is to announce some networks. Networks can only be ...


4

Port fast bypasses the usual STP phases and goes straight into forwarding. This is useful for ports connected to end-devices which use DHCP. It does not stop BPDUs, and there are those who advocate using it on all ports, although Cisco has a different take on it: Caution: Never use the PortFast feature on switch ports that connect to other switches, hubs,...


4

You don't have an Area 0. Areas can only talk to Area 0. This is an OSPF basic feature which helps prevent routing loops. Router 1 needs to be in Area 0. Try something like this: Router0: interface Serial2/0 ip address 20.1.1.2 255.255.255.252 ! router ospf 1 network 20.1.1.0 0.0.0.3 area 1 ! Router1: interface Loopback0 ip address 20.0.0.1 255.255....


4

It appears that some of your ports are in VLANs that do not have ip helper addresses on the router. They won't get addresses from your server.


4

Packet tracer is a simulator unlike GNS3 which is an emulator. so you cant run linux guest os in packet tracer


4

With this ACL: ip access-list extended IT_SEGMENT permit ip 10.1.10.0 0.0.0.31 10.1.30.0 0.0.0.31 ! You are limiting traffic coming in from that interface to only the 10.1.30.0/27 network because there is an implicit deny all at the end of the ACL. Also, remember that most network protocols work with a request/reply, and you are limiting what can be ...


4

You can use the ping command for choosing Extended commands options: Router#ping Protocol [ip]: Target IP address: 10.0.12.1 Repeat count [5]: 10 Datagram size [100]: Timeout in seconds [2]: Extended commands [n]: y Source address or interface: 1.1.1.1 ... the <cr> it stands for "Carriage Return." it means that, you can just click enter and ...


4

DCE stands for data circuit-terminating, data communications, or data carrier equipment - this is a modem or more generally, a line adapter. DTE stands for data terminal equipment which generally is a terminal or a computer. Basically, these two are the different ends of a serial line.


4

Remember that IPv6 doesn't use ARP. There is no broadcast on IPv6, and ARP uses broadcast. IPv6 uses ND, which uses multicast. Notice the difference in the route configurations: ipv6 route 2004::/64 GigabitEthernet0/2 ipv6 route 2005::/64 2003::2 ! You are not giving an actual next hop address for the network on the other side of R2. If you point the ...


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