Category:   Quiz

Your company has an IPsec tunnel with another company for achieving network connectivity between servers in 10.10.10.0/24 on your side to 10.20.20.0/24 on theirs. Lately they complained that their equipment has problems dealing with ESP and requested to migrate this existing IPsec tunnel from Encapsulating Security Payloads (ESP) to Authentication Headers (AH), since encryption/confidentiality was never a requirement for this tunnel. What could go wrong ?

Company ABC has multiple buildings and two internet connections via 2 different ISPs. Both BR-B and BR-C receive a default route via eBGP from the ISPs and they inject it in OSPF. For some reason, when ISP-1 link goes down, entire Building-A looses the internet access ! Something must be wrong...

Company ABC runs a static VTI-based VPN tunnel between Site-1, hosting 192.168.1.1, and Site-2, hosting 192.168.5.5. BGP is configured between the two sites, over the VTI Tunnel, making all traffic between the sites to be encrypted/protected by IPsec. The network engineer tries to configure QoS but something does not work !...

Your company has 3 sites, each with a dedicated border router, R1, R2 and R3.
Site-1 (R1) and Site-2 (R2) have their own internet uplinks, but Site-3 (R3) connects to internet via R2. A GRE tunnel is built between R2 and R3 and applied an MTU of 1440, due to some constraints in the transit network between them. You notice that traffic between same pair of devices works for TCP 1001 but fails for TCP 1002. What's wrong ?

You have just received a nice job at a big enterprise that has multiple sites connected over their own managed MPLS Core. Each site runs EIGRP as the CE - PE routing protocol. You get the task to route some traffic in a particular way, but you cannot make it. What is missing ?

Your company has a border router (R2) that is connected to two partner companies: Partner-DB (R1) providing database services and Partner-APP (R3) that provides different application services to your web servers in DMZ (200.200.200.0/24). You are requested to configure NAT according to some requirements.

As a senior network administrator, you receive complaints from server team that yesterday there were multiple short network cuts that impacted some very sensitive applications running in the data center. You investigate and find out that one of the level 1 network engineers performed some network changes. What went wrong?

Company ABC is in process of configuring BGP Confederations between its sites. During a small transition period, there will be no BGP between R3 and R2, but instead only static routing. Have a look at the quiz and try answering the question !

Your network is up and running without any complaints for few months. All good, until one single link creates problems in the entire network, although it was supposed to be redundant. What's wrong ?

Your network follows a standard 3 tier hierarchical design (Core, Distribution, Access) and has two WAN circuits with eBGP sessions with the ISPs. You want to push the default route down to the Distribution routers, but something goes wrong. Where is the mistake?

You have recently joined a new company that still uses Frame Relay. For monitoring purposes, you implement a script that pings all interfaces of a router, but you notice that some of them are not ping-able. Why ?

Company ABC closes a deal with a Partner Company that requires redundant network paths between the two networks. Two connections are installed between the companies, but the traffic seems to go over the slower one. Why ?

Your company makes a new contract with a Partner Company for a new research project. To provide network connectivity, NAT is being configured on your side but something does not work as desired. What is it?

Company ABC has multiple offices interconnected via an MPLS provider and each office runs OSPF with a separate Area number.
In one of the offices, there is an internal router that uses VRFs. You notice that some routes are not learned. Why ?