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Network Configuration—PPPThere may be certain cases when you are running multiple PPPoE servers, each fora specific group of clients, and each group is distinguished using a provider nametag. This can be set in the PPPoE client settings. Your PPPoE server then picks onlythe incoming requests whose provider name tag matches with the one you specifiedin your configuration.And finally the last line in your configuration specifies some parameters such asthe PID file location (using -P parameter), and the name of the PPPoE server thatis returned to the clients (in this case server1 using the -a parameter), and finallythe relevant tag name in the ppp.conf configuration file is specified using the -lparameter (in this example, pppoe-in tag is used). You can change this informationto reflect your setup.Final step is to modify the ppp.conf configuration file and then create a ppp.secretfile as the user database.In our example, we specified the pppoe-in tag in the PPP configuration file to beused (hence the -l parameter). So your ppp.conf file looks like this:pppoe-in:enable papenable chapallow mode directenable proxydisable ipv6cpset mru 1492set mtu 1492set ifaddr 10.0.0.1 10.0.0.100-10.0.0.199set speed syncset timeout 0enable lqraccept dnsallow users *There are some magical parameters in this configuration file, which if missed willlead to major issues with your PPPoE server deployment. Two of the most importantparameters to be configured correctly would be MTU and Maximum Receive Unit(MRU). The default frame size (and therefore the MTU and MRU) of a typicalEthernet frame is 1500 bytes. PPPoE introduces 8 bytes of protocol overhead inaddition to Ethernet frames. This is where you should reduce the MTU and MRUsize in order to compensate the overhead. The specified MTU and MRU size is infact 1500 – 8 =1492.[ 154 ]