Hot answers tagged

16

You can configure the auto rollback feature to revert to a previous configuration in case you lose access. First, you need to configure configuration archive on the router. For example: archive path flash: write-memory This stores the recent configuration in flash. Then when you're ready to make changes, type configure term revert time 5 <new ...


9

Routers do not change the MAC address, they completely strip off the layer-2 frame, losing any layer-2 information, e.g. MAC addressing. A router then routes the layer-3 packet that was encapsulated in the lost frame to a different interface, and it builds a new frame for the new interface. Remember that not all layer-2 protocols use MAC addressing, only the ...


8

By default, the shortest path will be the best path. If you notice, the first three are locally configured options that you can use to override any selections that would normally be made by the shortest path. For example, there may be times that you receive prefixes from multiple other ASes, but the AS with the shortest path has the lowest bandwidth, so you ...


7

It's depend upon your requirement actually . Source nat ensure souce IP addresse translation to configured translated IP address . The translation IP address can be single interface allocated ip address . Or pool of ip address ==> When Configuring single IP address allocated to interface i is referred as Port address translation (PAT) ==> When ...


7

So, let's say you have 2 interfaces on the router, with the 2 IP addresses. Let's say 192.168.1.1/24 on the first one and 176.16.1.1/24 on the other. Presuming you're on a Cisco router, if you issue the command "show ip route" you'll see an output which shows the 2 IPs labeled with an L and a C. L stands for Local, and C for connected. Meaning that ...


6

As mentioned by Ron, you can use no-export (Don't advertise to any eBGP peers) or no-advertise (Don't advertise to iBGP or eBGP peers) to achieve this. However, this may strain scalability issues if bringing on another eBGP peer which you do wish to advertise these to. What I'd recommend is applying an inbound route-map/policy-statement on AS200/DUT for the ...


6

For NAT to work, you must specify a standard access list to identify the traffic that should be NATted. You reference the access list (source list 1) correctly, but you have not created the access list. Correct NAT config would be: ip nat inside source list 1 interface GigabitEthernet0/0 overload access-list 1 permit 192.168.1.0 0.255.255.255 Your extended ...


6

A local address doesn't have a strict definition, but in this context it usually means an address on a subnet directly connected to the router. It could be public or private. While it's very common to use NAT to translate private addresses into public, that is not the only use. In enterprise networks, sometimes we translate private to private, or public to ...


6

ARP is a layer-2 thing -- it's how layer-2 address (MAC) is associated with a layer-3 address (IPv4). The router (any node) will only respond to ARP requests for addresses it owns -- the addresses assigned to it's interface(s) or aliases. It will silently ignore all others. If your router is setup to handle the ancient bad idea of proxy-arp, then yes, it ...


5

For Communication between different subnets packet has to reach router or layer3 devices to process this packet . If another networks is directly connected then forwards packets on basis of ARP table . If destination is on another networks means forwards packet to next hops on basis of route entry Configured on network . However layer2 device cannot ...


5

A router that is configured to route does not use the ip default-gateway. It uses the default route, and you have that in the configuration. Cisco has a document that explains the differences: Configuring a Gateway of Last Resort Using IP Commands : The ip default-gateway command differs from the other two commands. It should only be used when ip routing is ...


5

Trying to get true load balancing with different providers is a Sisyphean task. You can spend the rest of your career working on it, and never get it right. These are both T1 providers and almost anything that "matters" is 1 AS hop away. You would think bandwidth would balance out but it's pretty lopsided in most cases. Why is this the case? BGP ...


5

I would dare say that you are the victim of the simplistic view presented by network 101 (introduction to networking) courses. Let me start by quoting from ISO 7498 (the OSI reference model). The purpose of this Reference Model of Open Systems Interconnection is to provide a common basis for the coordination of standards development for the purpose of ...


4

As per diagram R1 can ping both R2 and R3 beacuse both networks are directly connected networks . To ensure ping successful from R2 & R3 routing need to be configured in R2 & R3 router R2 Router IP route 192.168 .2.18 255.255.255.255 pointing towards gateway 192.168.2 .1 R3 Router IP route 192.168 .2.2 255.255.255.255 pointing towards gateway 192....


4

Let us know what model of cisco layer3 your are using in your configuration . Basically cisco catalyst layer3 switch interface are in "Switchport" mode to make interface in router mode #no Switchport mode " is used If using catalyst cisco layer3 switch But in your scenario switch interface is already in Switchport by default . Configure trunk ...


4

Administration value (AD) is nothing to be considered in border perspective of networks . AD value operation is limited with specific router configuration itself .. When multiple routing protocols are configured in router with route pointing to same destination . In this case router will make desicion to choose route among multiple route with different ...


4

Firstly your question itself is not providing required information to answer your query ! How your network topology seems to be .. Where your are creating a Vlans in router(inter-Vlan routing) or in layer3 switch (switch virtual interfàce). Usages of subnet pools is totally depends on your business requirements and how topology is designed. However your can ...


4

Port forwarding describes a layer-4 mechanism, operating on TCP connections or UDP packets without necessarily understanding the application data. Reverse proxy suggests a higher-layer (this is where the OSI model doesn't map directly to TCP/IP) application-aware proxy. In the old days, a proxy server was most commonly used between users and the Internet; ...


4

While an undo last is only supported by few devices, there are few alternatives: Before doing the tricky part, run a reload in 5:00. If you lose contact, the router will reboot a few minutes later. If everything does work out you cancel the reload: reload cancel. Instead of redefining a live connection, configure a new one and connect in parallel. Make sure ...


4

I am trying to figure out if an L3 switch is able to act as a switch for himself. That's a main point of an L3 switch. It switches on L2 and routes between VLANs. Is it possible to configure somehow the L3 Switch to act as a switch so that I can set up VRRP? Provided the L3 switch supports VRRP then yes, that's possible. For full functionality you need to ...


4

Under line you can define the default privilege level that user will get into when logging. Users could later escalate their privilege using enable. Keep in mind you have different line options (console, vty, etc) To answer your question - you can simply do privilege level 1 under line settings of the method you want to configure (virtual/console). For ...


4

You're missing a few keys. The index for NAT (or any connection tracking) is the src IP and port plus the dst IP and port. (Some systems even pay attention to TCP sequence numbers.) So a node can open up to 65535 connections to the same dst IP/port -- 192.168.1.1:[1-65535] to (www):80. Change either destination IP or port and it's a different set. Put ...


4

Encapsulation requires a protocol. Depending on the protocol, an encapsulating packet is uniquely identified by either EtherType (in layer 2), IP protocol number (in layer 3), transport-layer port number (in layer 4), enabling the gateway to handle the packet as required. The gateway commonly uses additional information from the encapsulating or underlying ...


3

Configuration mentioned above seems to be configured in router . If it is configured in router then there is no inter vlan routing is available . Two network are connected through router two interfàce . Two Vlans subnet networks will communicate by default as per your communication . No inter -Vlan routing is required to ensure communication between both ...


3

NAT overload configuration for translating private ip address to public address seems to be partially correct .But while nat translation private should translate to public ip which is configured on interfàce G0/0 . So ensure interfàce G0/0 should configured with ISP provided public ip address .. Further to reach traffic towards destination proper routing ...


3

Yes ! When ICMP traffic is initiated from source towards destination . It will fallow path for forward and reverse traffic depends upon routing method. Symentric routing If Configured symentric routing both forward and reverse traffic take same path . Asymentric routing If Configured Asymentric routing both forward and reverse traffic take different ...


3

No ! Generally access -list is configured in such way that outbound traffic initiated from LAN subnets only Assuming LAN subnet ip pool is 10.40.1.0/24 Then access list would be Router(config)#access-list 100 permit 10.40.1.0 0.0.0.255 any Router(config)#ip nat inside source list 100 interfàce gigabit Ethernet 0/0 overload So there will be no untranslated ...


3

It's not. Feasible at all to do inter-Vlan routing by deploying unmanaged switch inline . Unmanaged switch is not capable to create and modify and delete Vlans . So it's not feasible. To accomplish your requirement deploy managed switch and further connect end host to managed switch allowing specific Vlan .


3

As per your diagram both PC2 & PC3 should able to ping each other beacuse both networks are directly connected networks. No extra routing is required on router . When PC2 wants to ping PC3 . Traffic reaches to router from router Router will process this packet towards destionation by verifying ARP table in router . ARP table maps IPaddress mappes to màc ...


3

Hence Vlan is layer2 construct . By default same Vlans on can communicate to each other . In this scenario no routing is required and no router or layer3 devices is required . But in scenario where different Vlans wants to communicate .Router is required to route traffic between different Vlans . General by default different Vlan traffic won't communicate ...


Only top voted, non community-wiki answers of a minimum length are eligible