Assignment 2
Abbot and Costello
Abbott:
IP address 213.172.12.40 = 11010101 10101100 00001100 00101000
subnet mask 255.255.255.192 = 11111111 11111111 11111111 11000000
subnet 213.172.12.0 = 11010101 10101100 00001100 00000000
default gateway 213.172.12.1
Costello:
IP address 213.172.12.21 = 11010101 10101100 00001100 00010101
subnet mask 255.255.255.224 = 11111111 11111111 11111111 11100000
subnet 213.172.12.0 = 11010101 10101100 00001100 00000000
default gateway 213.172.12.1
1.Look at subnet masks to see how many hosts are implied on each local network
Abbott:
255.255.255.192 = 11111111 11111111 11111111 11000000
6 zeros, so 2^6 = 64 so its local netowork is x.x.x.00 to x.x.x.63 or x.x.x.0/26
Costello:
255.255.255.224 = 11111111 11111111 11111111 11100000
5 zeros, so 2^5 = 32 so its local network is x.x.x.00 to x.x.x 31 or x.x.x.0/27
================================================
IP ranges
Abbott: 213.172.12.40/26
Costello: 213.172.12.21/27
part 2 Exploration with Traceroute, Ping, and Ethereal
Here is a traceroute I did from my server to one of the ip addresses in the list below (link74-146.cent.net)
It looks like a router too.
[bjones@bill bjones]$ traceroute 199.232.74.146
traceroute to 199.232.74.146 (199.232.74.146), 30 hops max, 38 byte packets
1 lr.marlboro.edu (216.114.150.1) 0.298 ms 0.205 ms 0.169 ms
2 cisco1-s4-0-13-0.burl.sover.net (209.198.103.185) 5.985 ms 5.691 ms 5.593 ms
3 cisco1.wnskvtao.sover.net (207.136.212.234) 6.281 ms 5.617 ms 5.648 ms
4 s4-0.br0.brbovtma.vt.sover.net (64.17.120.2) 9.310 ms * 9.653 ms
Here is a traceroute I did from my server to dubya.marlboro.edu
1 lr.marlboro.edu (216.114.150.1) 0.272 ms 0.215 ms 0.170 ms
2 GCrouter.marlboro.edu (12.6.231.1) 1.959 ms 2.289 ms 3.727 ms
3 192.168.1.1 (192.168.1.1) 13.795 ms 12.723 ms 13.306 ms
4 dubya.marlboro.edu (10.1.2.15) 14.371 ms 14.211 ms 13.983 ms
Here is the traceroute I did on gradcenter
from my house
traceroute to gradcenter.marlboro.edu (216.114.150.5), 30 hops max, 40 byte packets
1 10.216.112.1 (10.216.112.1) 36 bytes to 192.168.1.100 25.97 ms 42.828 ms 18.637 ms
2 24.128.190.138 (24.128.190.138) 36 bytes to 192.168.1.100 11.28 ms 15.423 ms 11.874 ms
3 bar01-p4-0.wsfdhe1.ma.attbb.net (24.128.190.197) 36 bytes to 192.168.1.100 11.958 ms 23.4 ms 12.258 ms
4 24.218.190.49 (24.218.190.49) 36 bytes to 192.168.1.100 18.409 ms 17.321 ms 16.886 ms
5 12.125.33.33 (12.125.33.33) 36 bytes to 192.168.1.100 17.478 ms 20.53 ms 18.038 ms
6 gbr1-p60.cb1ma.ip.att.net (12.123.40.138) 36 bytes to 192.168.1.100 19.822 ms 22.243 ms 16.568 ms
7 tbr2-p013502.cb1ma.ip.att.net (12.122.5.57) 48 bytes to 192.168.1.100 19.152 ms 18.178 ms 19.488 ms
8 tbr2-cl5.cgcil.ip.att.net (12.122.10.106) 48 bytes to 192.168.1.100 41.595 ms 42.915 ms 41.109 ms
9 gar1-p390.chail.ip.att.net (12.123.216.217) 36 bytes to 192.168.1.100 40.834 ms 41.806 ms 38.51 ms
10 12.119.137.42 (12.119.137.42) 36 bytes to 192.168.1.100 57.958 ms 40.319 ms 38.932 ms
11 qcy1-br1-at-1-1-0.gnaps.net (199.232.42.94) 36 bytes to 192.168.1.100 62.997 ms 66.193 ms 62.773 ms
12 link74-146.cent.net (199.232.74.146) 36 bytes to 192.168.1.100 119.089 ms 221.537 ms 389.307 ms
13 64.17.120.13 (64.17.120.13) 36 bytes to 192.168.1.100 70.669 ms 71.492 ms 73.319 ms
14 cisco0.wnskvtao.sover.net (207.136.212.233) 36 bytes to 192.168.1.100 72.724 ms 72.887 ms 72.815 ms
15 mtc-gw.burl.sover.net (209.198.103.186) 48 bytes to 192.168.1.100 74.767 ms 82.15 ms 87.535 ms
16 zonorus.marlboro.edu (216.114.150.3) 48 bytes to 192.168.1.100 74.659 ms 98.894 ms *
This is what I captured with ethereal.
From what I can see, It looks like all connections come in through cisco0.wnskvtao.sover.net.
Its a cisco router.
Sover.net is the supplier of the internet for the college
No. Time Source Destination Protocol Info
1 0.000000 AppleCom_17:d1:8b Broadcast ARP Who has 192.168.1.33? Tell 192.168.1.100
this first packet was me getting a MAC address from my router 192.168.1.33
2 0.002455 Cisco-Li_c2:27:14 AppleCom_17:d1:8b ARP 192.168.1.33 is at 00:0f:66:c2:27:14
this is my router responding with its MAC address
3 0.002529 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33435
4 0.016086 10.216.112.1 192.168.1.100 ICMP Time-to-live exceeded
the first hop - 10.216.112.1
5 0.059308 192.168.1.100 ns10.attbi.com DNS Standard query PTR 1.112.216.10.in-addr.arpa
6 0.084112 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
7 0.102267 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33436
8 0.120620 10.216.112.1 192.168.1.100 ICMP Time-to-live exceeded
9 0.122573 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33437
10 0.135096 10.216.112.1 192.168.1.100 ICMP Time-to-live exceeded
11 0.138163 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33438
12 0.152626 24.128.190.138 192.168.1.100 ICMP Time-to-live exceeded
the second hop 24.128.190.138
13 0.153645 192.168.1.100 ns10.attbi.com DNS Standard query PTR 138.190.128.24.in-addr.arpa
14 0.184210 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
15 0.247226 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33439
16 0.262146 24.128.190.138 192.168.1.100 ICMP Time-to-live exceeded
17 0.263934 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33440
18 0.289347 24.128.190.138 192.168.1.100 ICMP Time-to-live exceeded
19 0.292504 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33441
20 0.304870 bar01-p4-0.wsfdhe1.ma.attbb.net 192.168.1.100 ICMP Time-to-live exceeded
the 3rd hop bar01-p4-0.wsfdhe1.ma.attbb.net
21 0.307501 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33442
22 0.326916 bar01-p4-0.wsfdhe1.ma.attbb.net 192.168.1.100 ICMP Time-to-live exceeded
23 0.328691 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33443
24 0.351687 bar01-p4-0.wsfdhe1.ma.attbb.net 192.168.1.100 ICMP Time-to-live exceeded
25 0.391510 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33444
26 0.426462 24.218.190.49 192.168.1.100 ICMP Time-to-live exceeded
27 0.427540 192.168.1.100 ns10.attbi.com DNS Standard query PTR 49.190.218.24.in-addr.arpa
28 1.132980 192.168.1.100 ns7.attbi.com DNS Standard query PTR 49.190.218.24.in-addr.arpa
29 1.280363 ns7.attbi.com 192.168.1.100 DNS Standard query response, No such name
30 1.360452 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33445
31 1.376382 24.218.190.49 192.168.1.100 ICMP Time-to-live exceeded
32 1.378179 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33446
33 1.398892 24.218.190.49 192.168.1.100 ICMP Time-to-live exceeded
34 1.402163 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33447
35 1.420420 12.125.33.33 192.168.1.100 ICMP Time-to-live exceeded
36 1.421580 192.168.1.100 ns10.attbi.com DNS Standard query PTR 33.33.125.12.in-addr.arpa
37 1.446054 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
38 1.507445 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33448
39 1.523589 12.125.33.33 192.168.1.100 ICMP Time-to-live exceeded
40 1.528793 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33449
41 1.549113 12.125.33.33 192.168.1.100 ICMP Time-to-live exceeded
42 1.551869 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33450
43 1.569628 gbr1-p60.cb1ma.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
44 1.572125 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33451
45 1.589600 192.168.1.100 ns10.attbi.com DNS Standard query PTR 5.150.114.216.in-addr.arpa
46 1.593706 gbr1-p60.cb1ma.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
47 1.595400 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33452
48 1.616822 gbr1-p60.cb1ma.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
49 1.647990 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33453
50 1.671431 tbr2-p013502.cb1ma.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
51 1.673802 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33454
52 1.695561 tbr2-p013502.cb1ma.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
53 1.702692 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33455
54 1.720900 tbr2-p013502.cb1ma.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
55 1.725629 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33456
56 1.774025 tbr2-cl5.cgcil.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
57 1.783450 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33457
58 1.825002 ns10.attbi.com 192.168.1.100 DNS Standard query response, Server failure
59 1.825610 tbr2-cl5.cgcil.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
60 1.825856 192.168.1.100 ns7.attbi.com DNS Standard query PTR 5.150.114.216.in-addr.arpa
61 1.827888 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33458
62 1.876632 tbr2-cl5.cgcil.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
63 1.879627 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33459
64 1.931862 gar1-p390.chail.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
65 1.942151 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33460
66 1.981437 gar1-p390.chail.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
67 1.983536 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33461
68 1.999503 ns7.attbi.com 192.168.1.100 DNS Standard query response PTR gradcenter.marlboro.edu
69 2.006672 192.168.1.100 ns10.attbi.com DNS Standard query PTR 1.112.216.10.in-addr.arpa
70 2.037869 gar1-p390.chail.ip.att.net 192.168.1.100 ICMP Time-to-live exceeded
71 2.041258 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33462
72 2.085451 12.119.137.42 192.168.1.100 ICMP Time-to-live exceeded
73 2.086604 192.168.1.100 ns10.attbi.com DNS Standard query PTR 42.137.119.12.in-addr.arpa
74 2.107046 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
75 2.127159 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
76 2.230575 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33463
77 2.272283 12.119.137.42 192.168.1.100 ICMP Time-to-live exceeded
78 2.274223 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33464
79 2.313784 12.119.137.42 192.168.1.100 ICMP Time-to-live exceeded
80 2.317008 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33465
81 2.380355 qcy1-br1-at-1-1-0.gnaps.net 192.168.1.100 ICMP Time-to-live exceeded
82 2.384696 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33466
83 2.448923 qcy1-br1-at-1-1-0.gnaps.net 192.168.1.100 ICMP Time-to-live exceeded
84 2.450933 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33467
85 2.515062 qcy1-br1-at-1-1-0.gnaps.net 192.168.1.100 ICMP Time-to-live exceeded
86 2.518547 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33468
87 2.585244 link74-146.cent.net 192.168.1.100 ICMP Time-to-live exceeded
88 2.589390 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33469
89 2.656302 link74-146.cent.net 192.168.1.100 ICMP Time-to-live exceeded
90 2.658180 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33470
91 2.724878 link74-146.cent.net 192.168.1.100 ICMP Time-to-live exceeded
92 2.728431 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33471
93 2.799551 64.17.120.13 192.168.1.100 ICMP Time-to-live exceeded
94 2.801706 192.168.1.100 ns10.attbi.com DNS Standard query PTR 13.120.17.64.in-addr.arpa
95 2.827540 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
96 2.840676 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33472
97 2.869235 192.168.1.100 ns10.attbi.com DNS Standard query PTR 19.76.240.63.in-addr.arpa
98 2.904409 ns10.attbi.com 192.168.1.100 DNS Standard query response PTR ns10.attbi.com
99 2.907043 192.168.1.100 ns10.attbi.com DNS Standard query PTR 138.190.128.24.in-addr.arpa
100 2.912615 64.17.120.13 192.168.1.100 ICMP Time-to-live exceeded
101 2.915413 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33473
102 2.932745 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
103 2.988261 64.17.120.13 192.168.1.100 ICMP Time-to-live exceeded
104 2.991269 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33474
105 3.090931 cisco0.wnskvtao.sover.net 192.168.1.100 ICMP Time-to-live exceeded
106 3.104783 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33475
107 3.178559 cisco0.wnskvtao.sover.net 192.168.1.100 ICMP Time-to-live exceeded
108 3.186284 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33476
109 3.260686 cisco0.wnskvtao.sover.net 192.168.1.100 ICMP Time-to-live exceeded
110 3.263612 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33477
111 3.356327 mtc-gw.burl.sover.net 192.168.1.100 ICMP Time-to-live exceeded
112 3.360144 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33478
113 3.391148 192.168.1.100 ns10.attbi.com DNS Standard query PTR 49.190.218.24.in-addr.arpa
114 3.438457 mtc-gw.burl.sover.net 192.168.1.100 ICMP Time-to-live exceeded
115 3.442510 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33479
116 3.456410 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
117 3.531606 mtc-gw.burl.sover.net 192.168.1.100 ICMP Time-to-live exceeded
118 3.535215 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33480
119 3.640177 zonorus.marlboro.edu 192.168.1.100 ICMP Destination unreachable
120 3.661197 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33481
121 4.475696 192.168.1.100 ns10.attbi.com DNS Standard query PTR 19.198.127.204.in-addr.arpa
122 4.611317 ns10.attbi.com 192.168.1.100 DNS Standard query response PTR ns7.attbi.com
123 4.616386 192.168.1.100 ns10.attbi.com DNS Standard query PTR 33.33.125.12.in-addr.arpa
124 4.643684 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
125 6.417337 192.168.1.100 ns10.attbi.com DNS Standard query PTR 42.137.119.12.in-addr.arpa
126 6.448279 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
127 6.824903 192.168.1.100 ns10.attbi.com DNS Standard query PTR 13.120.17.64.in-addr.arpa
128 6.849367 ns10.attbi.com 192.168.1.100 DNS Standard query response, No such name
129 8.662705 192.168.1.100 gradcenter.marlboro.edu UDP Source port: 34169 Destination port: 33482
130 8.741091 zonorus.marlboro.edu 192.168.1.100 ICMP Destination unreachable
Here are 2 arp packets I captured in promiscuous mode with tethereal.
These are broadcast from the router with the MAC name address 'Supermic_22:38:91'
to find the MAC address of the first ip addresses in the line.
these will go into arp cache once the MAC address is acquired.
3.182999 Supermic_22:38:91 -> Broadcast ARP Who has 216.114.150.52? Tell 216.114.150.1
3.862601 Supermic_22:38:91 -> Broadcast ARP Who has 216.114.150.83? Tell 216.114.150.1
Abbott can see costello, but Costello cant see Abbott.
1. Abbott sends a packet to Costello:
- Abbott broadcasts an ARP request to get costello's MAC address.
- Costello replies with a MAC address
- Abbot chches the MAC addres
- Abbott can send a packet directly to Costello
2 Describe what happens when costello sends a packet to abbott.
-Costello cant see Abbott in its network.
-Costello needs to sent the packet to the router, but doesnt have a MAC address for the router.
-Costello Broadcasts an ARP request to get the router's MAC address
-Router replies
-Costello sends the packet to Abbot via the router
3. Describe what happens at the router in each of these two scenarios.
with the first scenario, Abbot can get the MAC address of Costello because they are on the same network, so
Direct routing can be used.
with the second scenario, Costello thinks that Abbott is not on the same network, so he must use the default gateway and
hope the packet will get to Abbott. If the router is on the same network as Abbott, then it can send the packet on to Abbott
but if not, it might then send the packet to another router.
4. What subnet mask must the router have on the interface facing
these two hosts for communication to work?
at least 255.255.255.192
5. Describe why this might not be an optimal configration for these
two hosts.
- Too much work for the router.
- Slower communication
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