Complex PPP connection scenarios

Many networking scenarios use PPP to connect two hosts via modems or a dedicated serial line. While these scenarios may require some effort to achieve a successful connection, they are simple in that they only involve configuration of one connection. This section provides a description of two more complex scenarios that require multiple connections, including one or more PPP links, to resolve the scenario's networking needs.

PPP gateway scenario

The first complex connection scenario is illustrated by Figure 9-4, ``PPP gateway scenario''.

Figure 9-4 PPP gateway scenario

The requirements of this scenario are that host A needs to access the Internet but has no direct access. To gain Internet access, host A must use PPP to connect to host B, which does have Internet access. Host B must act as a gateway to the Internet for host A. This scenario requires that:

• a successful PPP link be established between host A and host B.

• host B be configured as a PPP gateway (see ``PPP gateway'').

• host B may need to have proxy ARP entries for other hosts to be able to send packets to host A (see ``Proxy ARP'').

• host A have a default route in its IP routing table that points to the PPP interface associated with the PPP link to host B. To add such a default route, you can use the command:
  
  route add default remote_IP_address

  remote_IP_address must be the remote IP address for the PPP link to host B.

PPP server scenario

The second complex connection scenario is illustrated by Figure 9-5, ``PPP server scenario''.

Figure 9-5 PPP server scenario

The requirements of this scenario are for a single host to act as a PPP server. Multiple hosts connect to this server using PPP, and the server provides services (such as Internet access) to these hosts over the PPP connections. There are two special configuration issues for a PPP server:

• the PPP server must be configured as a PPP gateway (see ``PPP gateway'')

• the PPP server must be represented by a unique IP address to each client.

If the server assigns addresses, this requires the following server configuration:

• The server must have an incoming remote access configuration in its /etc/ppphosts file for each client from which it will accept a PPP link request.

  ---

  NOTE: For servers that assign IP addresses from an IP address pool, it is possible to have more than one client log in using the same login accounts. This makes configuration simpler by requiring fewer PPP client accounts on the server.

  ---

• The server must specify unique local and remote IP addresses in each client entry. These addresses may be specified at configuration time for each entry, or a pool of IP addresses may be created from which PPP chooses when the link is brought up. For more information on how to implement this choice, see ``Configuring an endpoint for remote access''.

• Each client host must agree to use the remote and local IP addresses that the PPP server specifies for that client.

• The remote access endpoints configured on the server that will be used by the clients must permit IP address negotiation. That is, they must not specify the noipaddr configuration parameter.

• The remote access endpoints configured on the server that will be used by the clients must not specify local or remote IP addresses.

• Each client must specify unique remote and local IP addresses when negotiating for a PPP link with the server.

• Each client must support IP address negotiation with the server.

Home Notes Home MCSE MCSE MCITP + Security CCNA MCITP 2008  Boot Camp Schedule Register Frequently Asked Questions Course Fees Contact US Boot Camp Location Compare us to our competitors Testimonials Sitemap   Testimonials  Join MCSE MCITP Boot Camp & CCNA Boot Camp Back to Back Certification Today. links  270  290    291  293    294  298  299   Security  640-801  routing 811  821   831  Resources MCSE MCITP + CCNA  Training  Card pay  Papal  MCSE MCITP Notes  CCNA Notes    index main   root   link  resources home    Ref1 Ref2

Vibrant offers MCSE certification training boot camp for $5400 all inclusive, instructor led at California and Baltimore.

Vibrant Bootcamp Participants come from All Around the World. Vibrant has trained students from more than 15 countries like USA, UK, (Scotland, Ireland, Wales), Switzerland, Germany, Australia, Canada, France, Holland, Japan, Belgium, Bahrain, New Zealand, Tanzania, Turkey, Kenya and more.