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hoo2
2026-09-26 22:05:50 +03:00
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exercise/results/exp1-dhcp/dhcp-decoded.txt
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10:58:29.655251 12:07:f8:bf:6e:ff > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 12:07:f8:bf:6e:ff, length 300, xid 0xecb5a2e, Flags [none] (0x0000)
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Hostname Option 12, length 10: "mininet-vm"
Parameter-Request Option 55, length 13:
Subnet-Mask, BR, Time-Zone, Default-Gateway
Domain-Name, Domain-Name-Server, Option 119, Hostname
Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
NTP
10:58:29.655633 82:3b:16:e9:bb:17 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.131 tell 192.168.1.1, length 28
10:58:30.662723 82:3b:16:e9:bb:17 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.131 tell 192.168.1.1, length 28
10:58:31.687064 82:3b:16:e9:bb:17 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.131 tell 192.168.1.1, length 28
10:58:32.214530 12:07:f8:bf:6e:ff > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 12:07:f8:bf:6e:ff, length 300, xid 0xecb5a2e, secs 3, Flags [none] (0x0000)
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Hostname Option 12, length 10: "mininet-vm"
Parameter-Request Option 55, length 13:
Subnet-Mask, BR, Time-Zone, Default-Gateway
Domain-Name, Domain-Name-Server, Option 119, Hostname
Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
NTP
10:58:32.670822 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype IPv4 (0x0800), length 62: (tos 0x0, ttl 64, id 28856, offset 0, flags [DF], proto ICMP (1), length 48)
192.168.1.1 > 192.168.1.131: ICMP echo request, id 21591, seq 0, length 28
10:58:32.670897 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype IPv4 (0x0800), length 342: (tos 0xc0, ttl 64, id 52736, offset 0, flags [none], proto UDP (17), length 328)
192.168.1.1.67 > 192.168.1.131.68: [udp sum ok] BOOTP/DHCP, Reply, length 300, xid 0xecb5a2e, Flags [none] (0x0000)
Your-IP 192.168.1.131
Server-IP 192.168.1.1
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Offer
Server-ID Option 54, length 4: 192.168.1.1
Lease-Time Option 51, length 4: 43200
RN Option 58, length 4: 21600
RB Option 59, length 4: 37800
Subnet-Mask Option 1, length 4: 255.255.255.0
BR Option 28, length 4: 192.168.1.255
Default-Gateway Option 3, length 4: 192.168.1.1
10:58:32.671193 12:07:f8:bf:6e:ff > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 12:07:f8:bf:6e:ff, length 300, xid 0xecb5a2e, secs 3, Flags [none] (0x0000)
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Request
Server-ID Option 54, length 4: 192.168.1.1
Requested-IP Option 50, length 4: 192.168.1.131
Hostname Option 12, length 10: "mininet-vm"
Parameter-Request Option 55, length 13:
Subnet-Mask, BR, Time-Zone, Default-Gateway
Domain-Name, Domain-Name-Server, Option 119, Hostname
Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
NTP
10:58:32.673025 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype IPv4 (0x0800), length 342: (tos 0xc0, ttl 64, id 52738, offset 0, flags [none], proto UDP (17), length 328)
192.168.1.1.67 > 192.168.1.131.68: [bad udp cksum 0x851a -> 0x5896!] BOOTP/DHCP, Reply, length 300, xid 0xecb5a2e, secs 3, Flags [none] (0x0000)
Your-IP 192.168.1.131
Server-IP 192.168.1.1
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: ACK
Server-ID Option 54, length 4: 192.168.1.1
Lease-Time Option 51, length 4: 43200
RN Option 58, length 4: 21600
RB Option 59, length 4: 37800
Subnet-Mask Option 1, length 4: 255.255.255.0
BR Option 28, length 4: 192.168.1.255
Hostname Option 12, length 10: "mininet-vm"
Default-Gateway Option 3, length 4: 192.168.1.1
10:58:32.678132 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype IPv4 (0x0800), length 342: (tos 0xc0, ttl 64, id 52737, offset 0, flags [none], proto UDP (17), length 328)
192.168.1.1.67 > 192.168.1.131.68: [udp sum ok] BOOTP/DHCP, Reply, length 300, xid 0xecb5a2e, secs 3, Flags [none] (0x0000)
Your-IP 192.168.1.131
Server-IP 192.168.1.1
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Offer
Server-ID Option 54, length 4: 192.168.1.1
Lease-Time Option 51, length 4: 43200
RN Option 58, length 4: 21600
RB Option 59, length 4: 37800
Subnet-Mask Option 1, length 4: 255.255.255.0
BR Option 28, length 4: 192.168.1.255
Default-Gateway Option 3, length 4: 192.168.1.1
10:58:37.831406 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.131 tell 192.168.1.1, length 28
10:58:37.831440 12:07:f8:bf:6e:ff > 82:3b:16:e9:bb:17, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Reply 192.168.1.131 is-at 12:07:f8:bf:6e:ff, length 28
exercise/results/exp1-dhcp/dhcp.pcap
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exercise/results/exp1-dhcp/execution.txt
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mininet@mininet-vm:~/Networks-II/exercise$ sudo python3 ../source/build_network.py topology.json
Generated: topology.generated.py
mininet> h1 rm -f /var/lib/dhcp/dhclient.leases
mininet> h1 rm -f /tmp/dhcp.pcap
mininet> h1 tcpdump -i h1-eth0 -n -w /tmp/dhcp.pcap &
mininet> h1 ps aux | grep tcpdump
tcpdump: listening on h1-eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
tcpdump 4196 0.0 0.1 10904 5920 pts/2 S+ 10:57 0:00 tcpdump -i h1-eth0 -n -w /tmp/dhcp.pcap
root 4199 0.0 0.0 9368 2548 pts/2 S+ 10:58 0:00 grep tcpdump
mininet> h1 dhclient h1-eth0
mininet> h1 pkill -INT tcpdump
12 packets captured
12 packets received by filter
0 packets dropped by kernel
mininet> h1 tcpdump -n -e -vv -r /tmp/dhcp.pcap
reading from file /tmp/dhcp.pcap, link-type EN10MB (Ethernet)
10:58:29.655251 12:07:f8:bf:6e:ff > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 12:07:f8:bf:6e:ff, length 300, xid 0xecb5a2e, Flags [none] (0x0000)
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Hostname Option 12, length 10: "mininet-vm"
Parameter-Request Option 55, length 13:
Subnet-Mask, BR, Time-Zone, Default-Gateway
Domain-Name, Domain-Name-Server, Option 119, Hostname
Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
NTP
10:58:29.655633 82:3b:16:e9:bb:17 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.131 tell 192.168.1.1, length 28
10:58:30.662723 82:3b:16:e9:bb:17 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.131 tell 192.168.1.1, length 28
10:58:31.687064 82:3b:16:e9:bb:17 > ff:ff:ff:ff:ff:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.131 tell 192.168.1.1, length 28
10:58:32.214530 12:07:f8:bf:6e:ff > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 12:07:f8:bf:6e:ff, length 300, xid 0xecb5a2e, secs 3, Flags [none] (0x0000)
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Hostname Option 12, length 10: "mininet-vm"
Parameter-Request Option 55, length 13:
Subnet-Mask, BR, Time-Zone, Default-Gateway
Domain-Name, Domain-Name-Server, Option 119, Hostname
Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
NTP
10:58:32.670822 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype IPv4 (0x0800), length 62: (tos 0x0, ttl 64, id 28856, offset 0, flags [DF], proto ICMP (1), length 48)
192.168.1.1 > 192.168.1.131: ICMP echo request, id 21591, seq 0, length 28
10:58:32.670897 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype IPv4 (0x0800), length 342: (tos 0xc0, ttl 64, id 52736, offset 0, flags [none], proto UDP (17), length 328)
192.168.1.1.67 > 192.168.1.131.68: [udp sum ok] BOOTP/DHCP, Reply, length 300, xid 0xecb5a2e, Flags [none] (0x0000)
Your-IP 192.168.1.131
Server-IP 192.168.1.1
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Offer
Server-ID Option 54, length 4: 192.168.1.1
Lease-Time Option 51, length 4: 43200
RN Option 58, length 4: 21600
RB Option 59, length 4: 37800
Subnet-Mask Option 1, length 4: 255.255.255.0
BR Option 28, length 4: 192.168.1.255
Default-Gateway Option 3, length 4: 192.168.1.1
10:58:32.671193 12:07:f8:bf:6e:ff > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 328)
0.0.0.0.68 > 255.255.255.255.67: [udp sum ok] BOOTP/DHCP, Request from 12:07:f8:bf:6e:ff, length 300, xid 0xecb5a2e, secs 3, Flags [none] (0x0000)
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Request
Server-ID Option 54, length 4: 192.168.1.1
Requested-IP Option 50, length 4: 192.168.1.131
Hostname Option 12, length 10: "mininet-vm"
Parameter-Request Option 55, length 13:
Subnet-Mask, BR, Time-Zone, Default-Gateway
Domain-Name, Domain-Name-Server, Option 119, Hostname
Netbios-Name-Server, Netbios-Scope, MTU, Classless-Static-Route
NTP
10:58:32.673025 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype IPv4 (0x0800), length 342: (tos 0xc0, ttl 64, id 52738, offset 0, flags [none], proto UDP (17), length 328)
192.168.1.1.67 > 192.168.1.131.68: [bad udp cksum 0x851a -> 0x5896!] BOOTP/DHCP, Reply, length 300, xid 0xecb5a2e, secs 3, Flags [none] (0x0000)
Your-IP 192.168.1.131
Server-IP 192.168.1.1
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: ACK
Server-ID Option 54, length 4: 192.168.1.1
Lease-Time Option 51, length 4: 43200
RN Option 58, length 4: 21600
RB Option 59, length 4: 37800
Subnet-Mask Option 1, length 4: 255.255.255.0
BR Option 28, length 4: 192.168.1.255
Hostname Option 12, length 10: "mininet-vm"
Default-Gateway Option 3, length 4: 192.168.1.1
10:58:32.678132 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype IPv4 (0x0800), length 342: (tos 0xc0, ttl 64, id 52737, offset 0, flags [none], proto UDP (17), length 328)
192.168.1.1.67 > 192.168.1.131.68: [udp sum ok] BOOTP/DHCP, Reply, length 300, xid 0xecb5a2e, secs 3, Flags [none] (0x0000)
Your-IP 192.168.1.131
Server-IP 192.168.1.1
Client-Ethernet-Address 12:07:f8:bf:6e:ff
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Offer
Server-ID Option 54, length 4: 192.168.1.1
Lease-Time Option 51, length 4: 43200
RN Option 58, length 4: 21600
RB Option 59, length 4: 37800
Subnet-Mask Option 1, length 4: 255.255.255.0
BR Option 28, length 4: 192.168.1.255
Default-Gateway Option 3, length 4: 192.168.1.1
10:58:37.831406 82:3b:16:e9:bb:17 > 12:07:f8:bf:6e:ff, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.131 tell 192.168.1.1, length 28
10:58:37.831440 12:07:f8:bf:6e:ff > 82:3b:16:e9:bb:17, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Reply 192.168.1.131 is-at 12:07:f8:bf:6e:ff, length 28
mininet> exit
exercise/topology.generated.py
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#!/usr/bin/env python3
"""Generated Mininet topology. Do not edit by hand."""
import shlex
from mininet.cli import CLI
from mininet.link import TCLink
from mininet.net import Mininet
def _shell_join(args):
"""Quote command arguments for execution inside a Mininet node."""
return ' '.join(shlex.quote(str(arg)) for arg in args)
def _node_cmd(node, *args):
"""Execute one safely quoted command inside a Mininet node."""
return node.cmd(_shell_join(args))
def _start_background(node, args, log_path):
"""Start one background process and return its shell PID."""
command = _shell_join(args)
shell_command = (
command
+ ' >'
+ shlex.quote(log_path)
+ ' 2>&1 & echo $!'
)
return node.cmd('sh -c ' + shlex.quote(shell_command)).strip()
def main():
"""Build, configure, expose, and clean up the planned network."""
net = Mininet(controller=None, build=False)
nodes = {}
service_processes = []
try:
# Create nodes.
nodes['h1'] = net.addHost('h1', ip=None)
nodes['h2'] = net.addHost('h2', ip=None)
nodes['h3'] = net.addHost('h3', ip=None)
nodes['s1'] = net.addSwitch('s1', failMode='standalone')
nodes['s2'] = net.addSwitch('s2', failMode='standalone')
nodes['r0'] = net.addHost('r0', ip=None)
# Create links.
net.addLink(
nodes['h1'],
nodes['s1'],
intfName1='h1-eth0',
intfName2='s1-eth0',
)
net.addLink(
nodes['h2'],
nodes['s1'],
intfName1='h2-eth0',
intfName2='s1-eth1',
)
net.addLink(
nodes['h3'],
nodes['s2'],
intfName1='h3-eth0',
intfName2='s2-eth0',
)
net.addLink(
nodes['r0'],
nodes['s1'],
intfName1='r0-eth0',
intfName2='s1-eth2',
)
net.addLink(
nodes['r0'],
nodes['s2'],
intfName1='r0-eth1',
intfName2='s2-eth1',
)
# Materialize the Mininet topology.
net.build()
net.start()
# Configure concrete interfaces.
_node_cmd(nodes['h1'], 'ip', '-4', 'addr', 'flush', 'dev', 'h1-eth0')
_node_cmd(nodes['h1'], 'ip', 'link', 'set', 'dev', 'h1-eth0', 'up')
_node_cmd(nodes['h2'], 'ip', '-4', 'addr', 'flush', 'dev', 'h2-eth0')
_node_cmd(nodes['h2'], 'ip', 'link', 'set', 'dev', 'h2-eth0', 'up')
_node_cmd(nodes['h3'], 'ip', '-4', 'addr', 'flush', 'dev', 'h3-eth0')
_node_cmd(nodes['h3'], 'ip', 'addr', 'add', '192.168.2.10/24', 'dev', 'h3-eth0')
_node_cmd(nodes['h3'], 'ip', 'link', 'set', 'dev', 'h3-eth0', 'up')
_node_cmd(nodes['r0'], 'ip', '-4', 'addr', 'flush', 'dev', 'r0-eth0')
_node_cmd(nodes['r0'], 'ip', 'addr', 'add', '192.168.1.1/24', 'dev', 'r0-eth0')
_node_cmd(nodes['r0'], 'ip', 'link', 'set', 'dev', 'r0-eth0', 'up')
_node_cmd(nodes['r0'], 'ip', '-4', 'addr', 'flush', 'dev', 'r0-eth1')
_node_cmd(nodes['r0'], 'ip', 'addr', 'add', '192.168.2.1/24', 'dev', 'r0-eth1')
_node_cmd(nodes['r0'], 'ip', 'link', 'set', 'dev', 'r0-eth1', 'up')
# Configure static default routes.
_node_cmd(nodes['h3'], 'ip', 'route', 'replace', 'default', 'via', '192.168.2.1', 'dev', 'h3-eth0')
# Apply node-level networking settings.
_node_cmd(nodes['r0'], 'sysctl', '-w', 'net.ipv4.ip_forward=1')
_node_cmd(nodes['r0'], 'sysctl', '-w', 'net.ipv4.conf.all.rp_filter=0')
_node_cmd(nodes['r0'], 'sysctl', '-w', 'net.ipv4.conf.default.rp_filter=0')
_node_cmd(nodes['r0'], 'sysctl', '-w', 'net.ipv4.conf.r0-eth0.rp_filter=0')
_node_cmd(nodes['r0'], 'sysctl', '-w', 'net.ipv4.conf.r0-eth1.rp_filter=0')
# Start planned services.
_node_cmd(nodes['r0'], 'rm', '-f', '/tmp/mininet-dnsmasq-0.leases', '/tmp/mininet-dnsmasq-0.pid')
pid = _start_background(
nodes['r0'],
['dnsmasq', '--no-daemon', '--conf-file=', '--port=0', '--bind-interfaces', '--dhcp-authoritative', '--interface=r0-eth0', '--dhcp-range=192.168.1.100,192.168.1.200,12h', '--dhcp-leasefile=/tmp/mininet-dnsmasq-0.leases', '--pid-file=/tmp/mininet-dnsmasq-0.pid', '--dhcp-option=3,192.168.1.1'],
'/tmp/mininet-dnsmasq-0.log',
)
service_processes.append((nodes['r0'], pid))
# DHCP clients are intentionally not started here.
# The assignment captures DHCP before dhclient is run manually.
CLI(net)
finally:
# Stop only the service processes started by this script.
for node, pid in reversed(service_processes):
if pid:
_node_cmd(node, 'kill', pid)
net.stop()
if __name__ == '__main__':
main()