# Chapter 6. PAP and CHAP

Starting with version 0.9.1 kppp supports directly the most commonly used form of PAP authentification. The section 'PAP and CHAP with kppp' will descripe how to make PAP and CHAP work with kppp in general, while the section 'PAP with kppp' will describe in detail how to take advantage of kppp's build in support for the most commonly encountered version of PAP wich is widely used by commercial Internet Service Providers (ISP).

# 6.1. PAP with kppp

There are two different ways to use PAP:

## 6.1.1. Client side authentication

This variant is used by many commercial ISPīs. It basically means that you (or your computer) must authenticate yourself to the ISPīs PPP server. The PPP server must not authenticate himself to your computer, but typically this is not necessary since you know which computer you are connected to (because the connection was established by yourself). So this is no major security issue. kppp supports this variant directly. See below for instruction how use this one.

If your ISP just gives you a username and a password and tells you to use PAP authentication you must use this variant.

## 6.1.2. Two way authentication

Same as above, but your computer requires the ISP PPP server to authenticate himself. In order to establish a connection, you must choose the authentication method Script based, not PAP, and you will have to manually edit `/etc/ppp/pap-secrets`. While kppp doesn't provide build in support for this variant -- it is nevertheless easy to establish a connection using this variant of PAP with kppp. The details are described in the previous section 'Using PAP and CHAP with kppp'.

## 6.1.3. Preparing kppp for PAP

1. Make sure that the `/etc/ppp/options` (and `˜/.ppprc` if you do have such a file) does not contain one of the arguments:

   - +pap

   - -pap

   - papcrypt

   - +chap

   - +ua

   - remotename

   It is very unlikely that one of those arguments is already in there, but just to be sure.

2. Start kppp

3. Click on Setup

4. Choose the account you want to use PAP with and click on Edit

5. Click on the Dial tab.

6. Select PAP in the checkbox Authentication

7. If you do not want to retype the password each time you dial in, select Store password. This will save the password. Make sure that nobody other than you has access to your account, otherwise this person will have access to your password.

8. That's it. Close the dialogs, type in your the username and password your ISP supplied to you and dial.