Use of next-hop-self versus Advertising DMZ
The demilitarized zone (DMZ) defines a shared network between ASs. The IP subnet used forthe DMZ link might or might not be owned by any of the networked ASs. As you havealready seen, the next-hop address learned from the EBGP peer is preserved within IBGP. It isimportant for the IGP to be able to reach the IP address denoted via the NEXT_HOP attributein the UPDATE message. One way to do this is for the DMZ subnet to be part of the IGP andhave the subnet advertised in the AS...
Troubleshooting RIPv2 and RIPng
Two configuration problems common to RIPv2 are mismatched versions and misconfigured authentication. Both difficulties are easy to discover with debugging, as Example 6-29 shows. Example 6-29. Debugging reveals mismatched versions and misconfigured authentication. Jemez#debug ip rip events RIP event debugging is on Jemez# RIP: ignored v1 packet from 172.25.150.249 (illegal version) RIP: ignored v2 packet from 172.25.150.249 (invalid authentication) Jemez# A more likel..
Converging to a New STP Topology
STP logic monitors the normal ongoing Hello process when the network topology is stable; when the Hello process changes, STP then needs to react and converge to a new STP topology. When STP has a stable topology, the following occurs: 1. The root switch generates a Hello regularly based on the Hello timer. 2. Each non-root switch regularly (based on the Hello timer) receives a copy of the root’s Hello on its RP. 3. Each switch updates and forwards the Hello out its Desi..
An MPLS-based network consists of routers and switches interconnected via transport facilities such as fiber links (see Figure 1-1). Customers connect to the backbone (core) network through multiservice edge (MSE) routers. The backbone comprises the core routers that provide high-speed transport and connectivity between the MSE routers. An MSE router contains different types of line cards and physical interfaces to provide Layer 2 and Layer 3 services, including ATM, FR, Ethe..
Vulnerabilities, Attacks, and Common Exploits
This section covers some of the vulnerabilities in TCP/IP and the tools used to exploit IP networks. TCP/IP is an open standard protocol, which means that both network administrators and intruders are aware of the TCP/IP architecture and vulnerabilities. Note There are a number of network vulnerabilities, such as insufficient password protection, lack of authentication mechanisms, use of unprotected routing protocols, and firewall holes. This section concentrates on TCP/IP..
