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Homework 3
Name: Dalat Bui
Email: dnbui@unity.ncsu.edu
Team #: 3
Current Function: Team Lead
Homework #: 3
Class: ECE470
Date of Submission: 10/04/02
Table of Contents:
Tasks for this homework are below. All pages must be posted in your personal web-root (www/yourid/hw3.html) on MONET (with any additional links from there, as appropriate).
Points are in parentesis (points go to individuals who submit it - this is NOT team-work, each person is responsible for his or her homework). Deliverables (items which must be submitted as part of this homeowerk) should be self-evident, however some are emphasised - for clarity - by having a (D) after them.
* Check-out the CSC402/ECE470 WEB pages (send us - instructors
and TAs) your comments, suggestions, etc.
* Make sure you read the CSC402/ECE470 NEWS at least once between classes.
* Make sure you have read/learned the material listed in the [Reading
Assignment] due by homework due date. This includes basics of HTML.
* HEARTBEAT MSG MUST BE POSTED on you WEB-SITE in the NET/TeamX/www/HB/
directory (even if you have submitted it by email earlier, you need
to go back and add it there). HB messages must be numbered as follows
HBz.html where z is the msg number.
>> Done.
* Web pages (10 points total)
* (5 points) Develop and attach your personal HTML/WWW home-page to
the team web-site via a clearly visible link at that site (D)
There is an account on monet.csc.ncsu.edu for your team (team1, team2
... to team16) - talk to your web-subteam about the password - you all
share the same space, so be careful.
>> Done.
* (2 points) You need to put your "personal"
directories into the directory tree /NET/TeamX/www/"yourid"
where X is "1", "2", etc., and "yourid"
is your eos user id. YOUR PAGES MUST PHYSICALLY RESIDE ON MONET in /NET/teamX/www/"yourid"
space!!
>> Done
* (3 points) You must protect the http access to that
area by your eos userid and your course password, i.e., your idnumber
(you will need to set that up - use http access facilities - talk to
the persons who set up your TEAM webserver). Please note that there
is a difference between the class web-server and the team web-server,
although they share some of the same web-space directories.
>> Done.
* Individual Experiments (5 points total)
[TOC]
1. GET A NOTEBOOK and make it your LAB Book. RECORD
in it all procedures and RESULTS OF ALL THE EXPERIMENTS BELOW. YOU WILL
NEED THE NOTEBOOK DURING YOUR TEST (inclass exam).
>> Done.
2. (2 points for proper web and directory-location
of hw3) In addtion, ALL RESULTS OF YOUR EXPERIMENTS and YOUR HOMEWORK
ANSWERS to items marked "ItemX" below, MUST BE POSTED ON YOUR
PERSONAL WEB PAGES ON THE MONET.CSC.NCSU.EDU. Posting is in the file
directory tree /NET/TeamX/www/"yourid"/hw3.html, this file
will contain any other links you wish to show us.
>> Done.
3. You MUST use HTML to submit results/reports/etc.
Word, Excell, postsript, pdf, etc. are NOT acceptable unless an explicit
permission is given for that by the instructor. Homeworks submitted
other than HTML format will not be accepted.
>> Done
4. (3 points for proper hw format) Your homework
page will have on it your name, your email address, your team number,
your current function in the team, homework number, class, date of submission,
and table of contents links that point to individual homework items.
You will separate this "header" information from the rest
of the page(s) via a horizontal bar or a similar "device".
>> Done
* IP Routing (General) (38 points total)
1. Become familiar with your "cart/pod".
Work with and learn from your team members who are responsible for setting
it up.
>> Done
2. AT NO TIME ARE YOU ALLOWED TO OPEN
ANY OF THE COMPUTERS ON YOUR CART/POD TO ADD OR REMOVE ANY OF THE ADAPTERS
OR OTHER ITEMS WITHOUT AN EXPLICIT PERMISSION FROM THE INSTRUCTOR or
THE STAFF. Once the cart/pod is set-up, there is absolutely no need
for individuals to physcially add or remove any of the cart/pod items
(at least not for the following set of experiments, your equipment team
should have done all the lead work in that area already). If you get
the urge, please first talk to your equipment group, and then to us.
>> Yes, Sir.
3. (5 points): Describe (in one paragraph)
the networking architecture of your cart/pod - you need to tell us the
logical structure and the physical structure, speed of machines, memory,
diskspace, how many and which networking cards (including manufacturer
name and card type/model), how the machines are interconnected (swich,
hub - manufacturer, type, etc.), what is the logical topology of the
network, what is the physical topology, etc. (D)
>> The sketch of our network's topology
is below:
There are four linux machines (Baker, Barlow, Braun, and Brindley) and a Windows 2000 Pro/Linux machine (Archie) in our pod. Physically, these computers are connected in a star topology in which the hub acts as a single point of failure. Logically, however, these computers are connected in a hierarchical Point-to-Point network. This is because the end nodes communicate through the distribution nodes. In this case, Braun is the distribution node. It acts as the gateway for the four end node computers. One of its ethernet cards is connected to the hub; the other one is connected to the switch. This switch has a firewall set up and it leads to the outside world (www). This way, we have access to the outside world through router Braun.
All three Linux computers (Baker, Barlow, and Braun) are Pentium MMX 200, which runs at 200Mhz. They each has approximately 128M RAM and two 3Com (100BaseXT) network cards. They three have Maxtor hard drives: Baker's is 2.2 Gigs, Barlow's is 3.0 Gigs, and Braun's is 4.0 Gigs.
Archie has a duel operating system (both Linux and Windows 2000 Pro are installed). It runs at 1.6MHz and has 260MB RAM. It has a 37.3 Gig Seagate Barracuda hard drive. This computer also has two network cards: a 3Com 802.3 card and a Miniport WAN card.
More information on these machines
can be found on our inventory page: [Inventory]
4. Learn all you can about routing
tables, and IP routing in general. Learn how to use arp, netstat, ipconfig/ifconfig,
route, tracert (or traceroute, as the case may be), ping, and nslookup
commands. Perform the following experiments related to direct and indirect
routing, masks and the concept of private and public networks.
o IBM AIX documentation
o Linux docs - see your Linux man pages
o NT docs (on-line help on the NT box, Microsoft Web site)
>> Done.
5. Carefully read the NT and Unix documentation
related to set-up and management of network adapters and interfaces
(all of it on-line or on the Web). Very carefully record the current
state of all your machines (ipconfig/ifconifg dump, netstat -rn dump,
etc) so that you can put it back together again at the end of you experiments.
>> Done.
Clear all bindings on all three machines. Consult your
equipment team on how to go about it. CAREFUL!! THIS DOES NOT MEAN REMOVE
ADAPTERS or REMOVE ADAPTER DRIVERS. If you do the latter, you will have
to re-install them. What you do is disable the adapters and clear out
the routing tables (NT boxes), or shutdown the adapter on unix boxes
(using ifconfig, for example) and flush its routing tables.
>> Done. To clear the bindings, we first
turn off all the adapters by using the command ifconfig ethX down.
Then we look at the routing table by typing the command netstat -rn
or route -n. (normally, when the adapters are turned off, the
entries in the routing table are also cleared out). If the entries are
still in the routing table, we manually deleted each of the entries
by typing the command: route del -net [IP_Address] netmask [Netmask]
dev [Ethernet_Device].
6. Select one machine to be your gateway
- it should have at least two Ethernet adapters - in the current set-up
it is already marked as such and it MUST be a Linux box. Reboot it.
Turn off all adapters, then activate one adapter on it. That is the
one that is connected to the PRIVATE VLan on your pod master switch
(usually the middle 8 ethernet ports). The switch will be marked 152.1.158.xx1
where xx is a number assigned to your pod (not the pod number, xx1 can
be 71 or 181, and similar). Set this gateway adapter to DHCP (pick eth0
if you wish).
>> We selected Braun to be our gateway.
The switch is marked 152.1.158.172. This port is connected to our eth0
interface. Therefore, we enabled the DHCP on this adapter by modifying
the file ifcfg-eth0 with the command: pico /etc/sysconfig/network-scripts/ifcfg-eth0.
In that file we added the line: "BOOTPROTO = dhcp."
7. Let DHCP assign it the first of
the IP numbers that will belong to you during part of the experiments.
It is something like 10.99.158.xx, where xx can be 31 or 51 or something
else.
>> The IP number assigned was 10.99.158.165.
8. (2 points) Check the "cart/pod
gateway" routing table using "netstat -rn". Record it,
need it for this homework (D). Make sure TIME OF THE DAY AND THE DATE
are part of record (this one and all later ones) (D).
>> The routing table recorded is below:
Date: 10/3
Time: 11:15 a.m.
> netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 10.99.158.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo 0.0.0.0 10.99.158.1 0.0.0.0 UG 40 0 0 eth0
Ping the adapter that you have activated, ping (with tracing, i.e., -R option on monet, -r 9 on NT boxes) the Default Gateway (ah, the default gateway - that is the one in the outside world, since the firewall - which gives you the DHCP number - has an outside address and the there are routers on campus which have to know it, you need to pick the closest router to that number - e.g., 152.1.158.1 for Withers, and Daniels, 152.14.16.1 for V2).
Date: 10/3
Time: 11:20 a.m. > ping -R -c 5 10.99.158.165 PING 10.99.158.165 (10.99.158.165) from 10.99.158.165 : 56(124) bytes of data. 64 bytes from 10.99.158.165: icmp_seq=1 ttl=255 time=0.226 ms RR: 10.99.158.165 10.99.158.165 10.99.158.165 10.99.158.165 64 bytes from 10.99.158.165: icmp_seq=2 ttl=255 time=0.082 ms (same route) 64 bytes from 10.99.158.165: icmp_seq=3 ttl=255 time=0.084 ms (same route) 64 bytes from 10.99.158.165: icmp_seq=4 ttl=255 time=0.070 ms (same route) 64 bytes from 10.99.158.165: icmp_seq=5 ttl=255 time=0.096 ms (same route) --- 10.99.158.165 ping statistics --- 5 packets transmitted, 5 received, 0% loss, time 3996ms rtt min/avg/max/mdev = 0.070/0.111/0.226/0.058 ms -------------- ++ Ping the Default Gateway > ping -c 5 10.99.158.1 PING 10.99.158.1 (10.99.158.1) from 10.99.158.165 : 56(84) bytes of data. 64 bytes from 10.99.158.1: icmp_seq=1 ttl=64 time=0.886 ms 64 bytes from 10.99.158.1: icmp_seq=2 ttl=64 time=0.735 ms 64 bytes from 10.99.158.1: icmp_seq=3 ttl=64 time=0.690 ms 64 bytes from 10.99.158.1: icmp_seq=4 ttl=64 time=0.747 ms 64 bytes from 10.99.158.1: icmp_seq=5 ttl=64 time=0.734 ms --- 10.99.158.1 ping statistics --- 5 packets transmitted, 5 received, 0% loss, time 4032ms rtt min/avg/max/mdev = 0.690/0.758/0.886/0.071 ms > ping -c 5 152.1.158.1 PING 152.1.158.1 (152.1.158.1) from 10.99.158.165 : 56(84) bytes of data. 64 bytes from 152.1.158.1: icmp_seq=1 ttl=255 time=1.27 ms 64 bytes from 152.1.158.1: icmp_seq=2 ttl=255 time=1.23 ms 64 bytes from 152.1.158.1: icmp_seq=3 ttl=255 time=1.23 ms 64 bytes from 152.1.158.1: icmp_seq=4 ttl=255 time=2.43 ms 64 bytes from 152.1.158.1: icmp_seq=5 ttl=255 time=1.19 ms --- 152.1.158.1 ping statistics --- 5 packets transmitted, 5 received, 0% loss, time 4039ms rtt min/avg/max/mdev = 1.194/1.474/2.438/0.483 ms
Ping with trace www.sdsc.edu. Capture the ping trail and include it into your homework. (D) Note the delay times, number of hops, etc.
Date: 10/3
Time: 11:30 a.m.
>ping -R -c 5 www.sdsc.edu PING www.sdsc.edu (198.202.75.101) from 10.99.158.165 : 56(124) bytes of data. 64 bytes from www.sdsc.edu (198.202.75.101): icmp_seq=1 ttl=245 time=113 ms RR: 10.99.158.165 poehub-6509msfc-2.ncstate.net (152.1.7.71) ncsudmz.ncni.net (128.109.23.66) ncsugsr-gw-to-ncni-oc48.ncni.net (128.109.52.5) rlgh1-gw-abilene-oc48.ncren.net (198.86.17.65) wash-atla.abilene.ucaid.edu (198.32.8.66) atla-hstn.abilene.ucaid.edu (198.32.8.34) hstn-losa.abilene.ucaid.edu (198.32.8.22) 198.32.11.119 64 bytes from www.sdsc.edu (198.202.75.101): icmp_seq=2 ttl=245 time=113 ms (same route) 64 bytes from www.sdsc.edu (198.202.75.101): icmp_seq=4 ttl=245 time=112 ms (same route) 64 bytes from www.sdsc.edu (198.202.75.101): icmp_seq=5 ttl=245 time=113 ms (same route) --- www.sdsc.edu ping statistics --- 5 packets transmitted, 4 received, 20% loss, time 4028ms rtt min/avg/max/mdev = 112.904/113.473/113.862/0.354 ms
9. (3 points) Print out arp table (D). Who do the different arp numbers you see belong to? (D) Why? (D)
Date: 10/3 Time: 11:32 a.m. > arp Address HWtype HWaddress Flags Mask Iface 10.99.158.1 ether 00:20:78:D2:02:11 C eth0
>> The IP number 10.99.158.1
belongs to the default gateway. This is the gateway of Braun (our router).
This IP is in the arp table because when the eth0 interface of Braun
was restarted and enabled, it only has the IP address of its gateway,
which was manually configured. Since it needs to send a packet to a
different network to ask for an IP, it first sends out an arp packet
to find out the hardware address of its default gateway. When the hardware
of address is found through the arp, Braun stores this entry in the
arp table. From there, it can send packets to its default gateway.
10. Trace the route between your machine
and monet.csc.ncsu.edu. Use both "ping -r 9 monet.csc.ncsu.edu"
or "ping -R monet" and tracert or traceroute.
Date: 10/3
Time: 11:35 a.m. > ping -R -c 3 monet.csc.ncsu.edu PING monet.csc.ncsu.edu (152.14.53.141) from 10.99.158.165 : 56(124) bytes of data. 64 bytes from monet.csc.ncsu.edu (152.14.53.141): icmp_seq=1 ttl=253 time=2.82 ms RR: 10.99.158.165 poehub-6509msfc-2.ncstate.net (152.1.7.71) cmdfhub-6509msfc-1.ncstate.net (152.14.50.2) monet.csc.ncsu.edu (152.14.53.141) cmdfhub-6509msfc-2.ncstate.net (152.1.7.73) poehub-6509msfc-2.ncstate.net (152.1.158.4) 10.99.158.165 64 bytes from monet.csc.ncsu.edu (152.14.53.141): icmp_seq=2 ttl=253 time=3.11 ms RR: 10.99.158.165 poehub-6509msfc-2.ncstate.net (152.1.7.71) cmdfhub-6509msfc-2.ncstate.net (152.14.50.3) monet.csc.ncsu.edu (152.14.53.141) cmdfhub-6509msfc-2.ncstate.net (152.1.7.73) poehub-6509msfc-1.ncstate.net (152.1.158.2) 10.99.158.165 64 bytes from monet.csc.ncsu.edu (152.14.53.141): icmp_seq=3 ttl=253 time=2.85 ms RR: 10.99.158.165 poehub-6509msfc-2.ncstate.net (152.1.7.71) cmdfhub-6509msfc-1.ncstate.net (152.14.50.2) monet.csc.ncsu.edu (152.14.53.141) cmdfhub-6509msfc-2.ncstate.net (152.1.7.73) poehub-6509msfc-2.ncstate.net (152.1.158.4) 10.99.158.165 --- monet.csc.ncsu.edu ping statistics --- 3 packets transmitted, 3 received, 0% loss, time 2018ms rtt min/avg/max/mdev = 2.828/2.933/3.116/0.143 ms ----------------------------------------------------------------------------- Date: 10/3
Time: 11:36 a.m. > traceroute monet.csc.ncsu.edu 1 poehub-6509msfc-2.ncstate.net (152.1.158.4) 2.319 ms 1.629 ms 1.644 ms 2 cmdfhub-6509msfc-2.ncstate.net (152.1.7.73) 1.963 ms 1.819 ms 1.921 ms 3 monet.csc.ncsu.edu (152.14.53.141) 1.570 ms 1.449 ms 1.393 ms
(2 points) Explain how an IP packet (e.g., ping packet) travels between your workstation to monet and back by discussing activities at layer 2 and 3 (IP and ARP translation, NAT, MACs, etc., and by tabulating the interfaces at each point along the traced route, starting with your machine going to monet and then back to your machine. (D)
>> To get to monet.csc.ncsu.edu (152.14.53.141) from 10.99.158.162 (Braun's IP address), Braun first compares the network addresses by AND'ing the two IP addresses. Since the source and destination network numbers are different, Braun knows that monet.csc.ncsu.edu is not in the same network as itself. Therefore, it looks up the arp table to get hardware address (2nd Layer) of the default gateway. It then sends to this default gateway, which is poehub-6509msfc-2.ncstate.net (152.1.7.71). From there, the gateway will route the packet to another router (3rd Layer) before the packet reaches monet.csc.ncsu.edu. At the last router before the packet reaches monet, the router also checks the arp table to get the physical address of monet. If the entry is in the table, the router sends the packet straight there. If not, it sends out an arp packet to ask for the physical address. To send the packet back to Braun, monet will go through the same step that Braun did. The reason that the IP addresses of the router between monet and Braun are sometimes different is that the packets go through different ports on the same router.
(6 points) Your table (D) should something like the following example (of course you need to fill in the question marks and appropriate IP numbers).
| Node |
Interface
|
IP Header Source
|
IP Header Destination
|
| Braun | 10.99.158.162 | 10.99.158.162 | 152.1.7.71 |
| poehub-6509msfc-2.ncstate.net | 152.1.7.71 | 152.1.7.71 | 152.14.50.2 |
| cmdfhub-6509msfc-1.ncstate.net | 152.14.50.2 | 152.14.50.2 | 152.14.53.141 |
| monet.csc.ncsu.edu | 152.14.53.141 | 152.14.53.141 | 152.1.7.73 |
| cmdfhub-6509msfc-2.ncstate.net | 152.1.7.73 | 152.1.7.73 | 152.1.158.2 |
| poehub-6509msfc-1.ncstate.net | 152.1.158.2 | 152.1.158.2 | 10.99.158.162 |
| Braun | N/A | N/A | N/A |
11. (2 points) Explain why the same nodes show different interface IP numbers going to EGRC (monet) than they have coming back. (D)
>> From Braun, the packet traveled through two different routers before it reaches monet. Since each router has many interfaces, a packet coming in from one interface and come out to another inteface doesn't mean that it's coming back the same way. That is, let's say that at a router, packet A comes in interface 0 and come out at interface 3. When it's coming back, it doesn't have to go in interface 3 and then go out at interface 0. It may go through the router in different interfaces. For example, the packet may go in interface 5 and then out at interface 1 on the way back from monet. Therefore, by traveling through different interfaces on the router(s) the packets have different source/destination addresses.
12. (2 points) What happend to 152.14.x.129 and 152.1.x.65 and similar gateway interfaces (IP numbers) that are relevant to monet and the machine from which you are pinging/tracing? Why do they not show on the trace? (D) In fact, why should they show up on any trace?
>> The machines with those IP addresses may have been configured not to report any ICMP messages. That is why the packets go through them but no information was obtained from them.
13. (2 points) Try pinging www.nsf.gov.
Do you get a reply? (D) If yes, why yes if not why not. (D)
>> Yes. There was a reply. This means that
www.nsf.gov is reachable and it was not configured to ignore ICMP messages.
Below is the obtained result:
Date: 10/3
Time: 11:55 a.m. > ping www.nsf.gov PING www.nsf.gov (128.150.4.107) from 10.99.158.165 : 56(84) bytes of data. 64 bytes from www.nsf.gov (128.150.4.107): icmp_seq=1 ttl=244 time=26.3 ms 64 bytes from www.nsf.gov (128.150.4.107): icmp_seq=2 ttl=244 time=26.2 ms 64 bytes from www.nsf.gov (128.150.4.107): icmp_seq=3 ttl=244 time=26.3 ms 64 bytes from www.nsf.gov (128.150.4.107): icmp_seq=4 ttl=244 time=26.2 ms 64 bytes from www.nsf.gov (128.150.4.107): icmp_seq=5 ttl=244 time=26.2 ms --- www.nsf.gov ping statistics --- 5 packets transmitted, 5 received, 0% loss, time 4043ms rtt min/avg/max/mdev = 26.243/26.290/26.331/0.107 ms
14. (1 points) Trace route to www.nsf.gov.
Can you do it? (D) If yes, why yes, if not why not? (D) Attach whatever
part of the trace route you have obtained. (D)
>> Yes, I could traceroute
www.nsf.gov. From the result, we could tell that the www.nsf.gov is
reachable, and it is 11 hops away from our network. The result is shown
below.
>traceroute www.nsf.gov 1 poehub-6509msfc-2.ncstate.net (152.1.158.4) 2.399 ms 1.678 ms 1.651 ms 2 ncsugw-gew3-1.ncstate.net (152.1.7.1) 1.757 ms 1.693 ms 1.746 ms 3 ncsugsr-gw-to-ncsu-lan.ncni.net (128.109.23.65) 1.819 ms 1.701 ms 1.776 ms 4 rlgh1-gw-to-ncni-oc48.ncren.net (128.109.52.4) 1.955 ms 1.833 ms 1.862 ms 5 abilene-gw.ncni.net (198.86.17.66) 25.435 ms 25.290 ms 25.388 ms 6 washng-wash.abilene.ucaid.edu (198.32.11.126) 25.759 ms 25.453 ms 25.466 ms 7 wash-abilene-oc48.maxgigapop.net (206.196.177.1) 25.498 ms 25.467 ms 25.555 ms 8 arlg-so3-1-0.maxgigapop.net (206.196.178.41) 25.698 ms 25.688 ms 25.719 ms 9 206.196.177.138 (206.196.177.138) 26.471 ms 26.275 ms 26.365 ms 10 stargate.nsf.gov (198.181.231.7) 26.579 ms 26.547 ms 26.481 ms 11 128.150.238.205 (128.150.238.205) 27.129 ms 27.296 ms 32.077 ms 12 www.nsf.gov (128.150.4.107) 26.458 ms * 26.271 ms
15. (3 points) Ping microsoft.com
- Can you see that machine? traceroute to it. Can you do it? Explain
what is happening. (D)
>> No, I could not ping nor traceroute www.microsoft.com. Microsoft
must have its ICMP function disabled for security reasons.
>ping www.microsoft.com PING www.microsoft.akadns.net (207.46.197.113) from 10.99.158.165 : 56(124) bytes of data. --- www.microsoft.akadns.net ping statistics --- 7 packets transmitted, 0 received, 100% loss, time 5999ms
16. (5 points) Change the settings on your machine to non-DHCP, but retain the IP number, gateway number and mask given to you by DHCP. It will still be a 10.99.yyy.xxx address. What is the smallest (tightest mask you can use on your machine) and still see (ping) the outside world? (e.g., www.sdsc.com). (D)
>> The tightest mask that
allows for ping to work is 255.255.255.0, which is also the default
netmask.
Show the routing table with that mask (D). N.B. 255.255.255.255
is the tightest possible mask, 255.255.0.0 is a much less tight (or
it is a looser) mask.
Date: 10/3 Time: 2:35 p.m. Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 10.99.158.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo 0.0.0.0 10.99.158.1 0.0.0.0 UG 40 0 0 eth0
17. (2 points) What is the mask that
is just on the "other" side of what works. (D) Explain. (D)Warning.
The mask that JUST works will very much depend on what your machine
IP number is.
>> The mask that is just on the "other" side of what works is 255.255.255.128.
In binary representation of:
255.255.255.0 => 11111111.11111111.11111111.00000000
255.255.255.128 => 11111111.11111111.11111111.10000000
By putting an extra bit 1 on the last octet, it become a different network.
* Private Network (22 points total) [TOC]
1. Activate the second adapter on your cart/pod gateway.
Make the IP number on that adapter 10.Z.1.1 (where Z is your team number).
>> Done
2. Activate IP forwarding. Print and
attach the routing table.
Date: 10/3 Time: 3:15 p.m. Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 10.99.158.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0 10.3.0.0 0.0.0.0 255.255.0.0 U 40 0 0 eth1 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo 0.0.0.0 10.99.158.1 0.0.0.0 UG 40 0 0 eth0
3. Activate adapters on your other
machines.
> Done.
4. Make one non-gateway machine adapters
run as 10.Z.1.4 and the other as 10.Z.1.195. In both cases use 10.Z.1.1
as the default gateway, and 152.1.1.206 as the DNS server.
> Done.
5. (3 points)What is the tightest
mask on the non-gateway machine that lets you ping 10.Z.1.1 from 10.Z.1.4?
(D)
Warning. When changing masks, it is best if you start with the tightest
mask and work towards looser masks. Also, you may want to reboot the
machine (or flush arp tables) every time since there may be some arp
memory that can skew your results.
>> The tightest mask is 255.255.255.248
6. (2 points)Can you see 10.Z.1.1 from monet? (D) Explain why yes/not? (D)
>> No. Because 10.Z.11 is a private network and it is behind a firewall. Therefore monet cannot see it.
7. (3 points)Can you see the gateway
router of the cart/pod-gateway machine from 10.Z.1.4? (D) Explain why
yes/not? (D)
>> Yes. Because they are on the same network.
8. (2 points)What is the tightest
mask on the non-gateway machine that lets you ping 10.Z.1.1 from 10.Z.1.195?
(D)
>> The tightest mask is 255.255.255.0
9. (2 points)What is the tightest mask on the non-gateway machines (need value for each non-gateway machine) that lets you ping 10.Z.1.4 from 10.Z.1.195? (D)
>> It's 255.255.255.0
10. (5 points) Attempt to multihome (on the cart/pod gateway) the 10.Z.1.1 adapter so that now it also carries 10.Z.1.65, 10.Z.1.129 and 10.Z.1.193 addresses.
Can you do that? (D)
>> By using the command ifconfig ethx:#, where # is a number, I was able to do that.
>ifconfig
eth0 Link encap:Ethernet HWaddr 00:50:04:E1:73:35
inet addr:10.99.158.162 Bcast:10.99.158.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2295 errors:11 dropped:0 overruns:0 frame:19
TX packets:490 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:283556 (276.9 Kb) TX bytes:52275 (51.0 Kb)
Interrupt:10 Base address:0xd880
eth1 Link encap:Ethernet HWaddr 00:C0:4F:BE:B1:E2
inet addr:10.3.1.1 Bcast:10.3.1.7 Mask:255.255.255.248
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:755 errors:1 dropped:0 overruns:0 frame:2
TX packets:642 errors:0 dropped:0 overruns:0 carrier:0
collisions:16 txqueuelen:100
RX bytes:78268 (76.4 Kb) TX bytes:183149 (178.8 Kb)
Interrupt:3 Base address:0xd840
eth1:1 Link encap:Ethernet HWaddr 00:C0:4F:BE:B1:E2
inet addr:10.3.1.65 Bcast:10.3.1.7 Mask:255.255.255.248
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Interrupt:3 Base address:0xd840
eth1:2 Link encap:Ethernet HWaddr 00:C0:4F:BE:B1:E2
inet addr:10.3.1.129 Bcast:10.3.1.7 Mask:255.255.255.248
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Interrupt:3 Base address:0xd840
eth1:3 Link encap:Ethernet HWaddr 00:C0:4F:BE:B1:E2
inet addr:10.3.1.193 Bcast:10.3.1.7 Mask:255.255.255.248
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Interrupt:3 Base address:0xd840
eth1:4 Link encap:Ethernet HWaddr 00:C0:4F:BE:B1:E2
inet addr:10.3.2.1 Bcast:10.255.255.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Interrupt:3 Base address:0xd840
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:10 errors:0 dropped:0 overruns:0 frame:0
TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:700 (700.0 b) TX bytes:700 (700.0 b)
If no, why not? If yes, change the gateway on the 10.Z.1.195
machine to be 10.Z.1.193. (D)
>> Done
What is the tightest mask you can now have (number for
each non-gateway machine needed) that lets you ping 10.Z.1.195 from
10.Z.1.4? (D)
>> At the interface 10.3.1.195, the tightest netmask is 255.255.255.248. At the interface 10.3.1.3, the tightest netmask is 255.255.255.248.
Can you ping 10.Z.1.4 from 10.Z.1.195? (D)
Yes. Even though they are on different networks, they can communicate with each other through the router (Layer 3 Function)..
11. Add one more adapter or multihome address to the cart/pod gateway machine to support the 10.Z.2 network (do not forget to turn on IP forwarding if you are using multihoming). Ping the other to machines.
If all is well the gateway should be able to route between the the two private subnets.
>> Done.
12. 5 points Change the address on the 10.Z.1.195 machine into 10.Z.2.195 and make it work via cart/pod-gateway router. Prove that it is working by doing a traceroute ping between 10.Z.2.195 and 10.Z.1.4 and by attaching a record of that trace (D) and record of routing tables on all three machines (D).
Date: 10/3 Time: 4:23 p.m.
Routing Table at Braun (Gateway) >netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 10.3.1.64 0.0.0.0 255.255.255.248 U 40 0 0 eth1 10.3.1.192 0.0.0.0 255.255.255.248 U 40 0 0 eth1 10.3.1.0 0.0.0.0 255.255.255.248 U 40 0 0 eth1 10.3.1.128 0.0.0.0 255.255.255.248 U 40 0 0 eth1 10.3.2.0 0.0.0.0 255.255.255.0 U 40 0 0 eth1 10.99.158.0 0.0.0.0 255.255.255.0 U 40 0 0 eth0 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo 0.0.0.0 10.99.158.1 0.0.0.0 UG 40 0 0 eth0
Routing Table at Barlow netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface
10.3.2.0 0.0.0.0 255.255.255.0 U 40 0 0 eth1
127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo
0.0.0.0 10.3.2.1 0.0.0.0 UG 40 0 0 eth1
Routing table at Baker >netstat -rn Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 10.3.1.0 0.0.0.0 255.255.255.248 U 40 0 0 eth0 127.0.0.0 0.0.0.0 255.0.0.0 U 40 0 0 lo 0.0.0.0 10.3.1.1 0.0.0.0 UG 40 0 0 eth0 ===================================================================================== >traceroute 10.3.2.195 1 10.3.1.1 (10.3.1.1) 1.115 ms 0.382 ms 0.338 ms 2 10.3.2.195 (10.3.2.195) 0.864 ms 0.595 ms 0.579 ms traceroute 10.3.1.4 1 10.3.2.1 (10.3.2.1) 1.018 ms 0.404 ms 0.353 ms 2 * 10.3.1.4 (10.3.1.4) 0.679 ms 0.396 ms ping -R 10.3.1.4 PING 10.3.1.4 (10.3.1.4) from 10.3.2.195 : 56(124) bytes of data. From 10.3.2.1: icmp_seq=1 Redirect Host(New nexthop: 10.3.1.4) 64 bytes from 10.3.1.4: icmp_seq=1 ttl=254 time=1.73 ms RR: 10.3.2.195 10.3.1.1 10.3.1.4 10.3.1.4 10.3.2.1 10.3.2.195 From 10.3.2.1: icmp_seq=2 Redirect Host(New nexthop: 10.3.1.4) 64 bytes from 10.3.1.4: icmp_seq=2 ttl=255 time=0.874 ms RR: 10.3.2.195 10.3.1.1 10.3.1.4 10.3.1.4 10.3.2.195 64 bytes from 10.3.1.4: icmp_seq=3 ttl=255 time=0.482 ms RR: 10.3.2.195 10.3.1.4 10.3.1.4 10.3.2.195 64 bytes from 10.3.1.4: icmp_seq=4 ttl=255 time=0.432 ms (same route) 10.3.1.4 ping statistics --- rtt min/avg/max/mdev = 0.432/0.881/1.736/0.522 m
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