Point To Point Protocol

NETWORKS PROTOCOLS

Point-to-Point Protocol (PPP)

Session Development
1- Check that the network is working properly: even though we want to connect the PCs using the serial ports, we also have to connect them to an Ethernet network using a Hub. That is the reason why the PCs, at the login, detect that a network is available and enable their network interfaces. Write the network interfacesavailable in LINUX machines, their Ethernet and IP addresses: ifconfig –a Write the routing tables of LINUX machines: netstat –r Execute a ping between the two machines. Write down the response time: From LINUX A: ping dir_IP_LINUX_B Answer Executing: ifconfig in LINUX B machine: LINUX B eth0 Link encap:Ethernet HWaddr 00:22:19:12:ad:d8 inet addr:147.83.40.66 Bcast:147.83.40.255 Mask:255.255.255.0inet6 addr: fe80::222:19ff:fe12:add8/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1901 errors:0 dropped:0 overruns:0 frame:1 TX packets:69 errors:0 dropped:0 overruns:0 carrier:0 collisions:9 txqueuelen:1000 RX bytes:187708 (183.3 KB) TX bytes:8698 (8.4 KB) Interrupt:17 eth1 Link encap:Ethernet HWaddr 00:0e:0c:7f:fd:ba UP BROADCAST MULTICAST MTU:1500 Metric:1 RXpackets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:2036 errors:0 dropped:0 overruns:0 frame:0 TX packets:2036 errors:0 dropped:0 overruns:0carrier:0 collisions:0 txqueuelen:0 RX bytes:101936 (99.5 KB) TX bytes:101936 (99.5 KB)

lo

Executing: master@aloha6:~$ netstat –r Kernel IP routing table Destination Gateway Genmask 192.168.85.0 * 255.255.255.0 172.16.116.0 * 255.255.255.0 147.83.40.0 * 255.255.255.0 link-local * 255.255.0.0 default gigacorc3-routi 0.0.0.0 Explanation of the routing table When gateway contains * it means thedestination network is a directly connected network and the « gateway » is the computer's network interface. Line with « default » is for the default route, it corresponds to the reserved network number 0.0.0.0 and the default gateway is used whenever there is no specific route in the table for a destination network address. Field flags: U means that the route is up and operational G indicates thatthe route use an external gateway Executing: ping 147.83.40.65 Response time: 0.32 ms 0.292 ms 0.291 ms 0.298 ms ……. 2- Check that the /etc/ppp/options file of both machines is empty (or with comment lines that begin with #). From LINUX-A execute: pppd 192.168.100.110: –detach local /dev/ttyS0 passive From LINUX-B execute: pppd 192.168.100.120: -detach local /dev/ttyS0 Observe the messages that haveappeared in the terminals. Execute again: ifconfig -a and netstat –r. Write and comment the differences with the former results. Write the response time of a ping between LINUX-A and LINUX-B using new interfaces. How has it changed?

Flags U U U U UG

MSS Window 00 0 00 0 00 0 00 0 00 0

irtt Iface vmnet8 vmnet1 eth0 eth0 eth0

Answer Executing root@aloha6:/etc/ppp# pppd 192.168.100.120:-detach local /dev/ttyS0 Using interface ppp0 Connect: ppp0 /dev/ttyS0 Deflate (15) compression enabled local IP address 192.168.100.120 remote IP address 192.168.100.110 When we execute again ifconfig -a after having executed the commands pppd 192.168.100.120: -detach local /dev/ttyS0 we can observe a new entry, ppp0. ppp0 Link encap:Point-to-Point Protocol inet addr:192.168.100.120P-t-P:192.168.100.110 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:4 errors:0 dropped:0 overruns:0 frame:0 TX packets:4 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:62 (62.0 B) TX bytes:62 (62.0 B)

Executing: root@aloha6:/home/usuari# netstat -nr Kernel IP routing table Destination Gateway 192.168.100.110 0.0.0.0 192.168.85.0...