Juniper JUNOSE 11.1.X - LINK LAYER CONFIGURATION 4-7-2010, Configuration Manual

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Authentication
The router acts as an authenticator. It demands authentication from a remote PPP
peer but refuses to authenticate itself.
Rate Limiting for PPP Control Packets
The router implements rate limiting for PPP control packets to protect the
corresponding PPP interface from denial-of-service (DoS) attacks. The interface
discards control packets when the rate of control packets received exceeds the rate
limit for PPP interfaces.
A PPP interface has a rate limit control that is non-configurable and always in effect;
the rate limit is the same for all PPP interfaces. In addition, each interface instance
maintains its own state and statistics counters for tracking the rate. The rate limit
for PPP control packets is approximately 10 packets per second.
For a PPP interface, the router increments the discards counter in the show ppp
interface command display to track the number of PPP control packets discarded
on receipt (in) or discarded before they were transmitted (out) on this interface.
For examples of the show ppp interface command display, see “show ppp interface”
on page 287.
Extensible Authentication Protocol
The JUNOSe software supports Extensible Authentication Protocol (EAP) for
authenticating a peer before allowing network layer protocols to transmit over the
link. EAP supports multiple authentication methods, including EAP-TLS and
EAP-MD5-Challenge. The EAP server and the peer negotiate the specific authentication
method to be used. Figure 34 on page 267 illustrates the three components required
for EAP: an EAP authenticator, an EAP server, and an EAP client.
Figure 34: Authentication with EAP
After LCP negotiation, JUNOSe starts the EAP negotiation process by initiating an
identity exchange with the EAP client on the peer. The router sends an EAP identity
request packet to the peer, which replies with an EAP identity response packet. After
this exchange, the E Series router acts only as a pass-through device, enabling the
EAP server residing on the backend authentication server to select and negotiate the
particular EAP authentication method directly with the EAP client on the peer.
Overview
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Chapter 8: Configuring Point-to-Point Protocol