Hitchhiker's Guide to Openbsd

ppp(8) variations
Many ISPs now offer xDSL services, which are faster than traditional dial-up methods. This includes 
variants such as ADSL and SDSL. Although no physical dialing takes place, connection is still based on 
the Point to Point Protocol. Examples include: 
●
PPPoE 
●
PPPoA 
●
PPTP 
PPPoE/PPPoA
The Point to Point Protocol over Ethernet (PPPoE) is a method for sending PPP packets in Ethernet 
frames. The Point to Point Protocol over ATM (PPPoA) is typically run on ATM networks, such as 
those found in the UK and Belgium. 
Typically this means you can establish a connection with your ISP using just a standard Ethernet card 
and Ethernet-based DSL modem (as opposed to a USB-only modem). 
If you have a modem which speaks PPPoE/PPPoA, it is possible to configure the modem to do the 
connecting. Alternatively, if the modem has a `bridge' mode, it is possible to enable this and have the 
modem "pass through" the packets to a machine running PPPoE software (see below). 
The main software interface to PPPoE/PPPoA on OpenBSD is 
pppoe(8)
, which is a userland 
implementation (in much the same way that we described 
ppp(8)
, above). A kernel PPPoE 
implementation, 
pppoe(4)
, has been incorporated into OpenBSD. 
PPTP
The Point to Point Tunneling Protocol (PPTP) is a proprietary Microsoft protocol. A pptp client is 
available which interfaces with 
pppd(8)
 and is capable of connecting to the PPTP-based Virtual Private 
http://www.openbsd.org/faq/faq6.html (15 of 33)9/4/2011 10:02:06 AM

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6 - Networking
Networks (VPN) used by some cable and xDSL providers. pptp itself must be installed from 
packages
 or 
ports
. Further instructions on setting up and using pptp are available in the man page which is installed 
with the pptp package.