CCIE R&S Advanced Technologies Class v4.5 - RIP Broadcast Updates, IP Directed Broadcast, IP Broadcast-Address, Smurf Attacks, Fraggle Attacks

Transcript

1	Introduction	0h 43m
2	Using the Cisco Documentation	0h 52m
3	Ethernet Overview, Layer 2 Switchports, Trunking, ISL, 802.1q, DTP	0h 47m
4	VTP, VTP Authentication, VTP Pruning	1h 02m
5	VTP Prune Eligible List, VTP Transparent, VTP Troubleshooting, Trunk Allowed List, Extended VLANs	0h 48m
6	VLAN and VTP Review	0h 19m
7	SVIs, Native Routed Interfaces, Router-on-a-Stick	0h 46m
8	Layer 2 EtherChannel, EtherChannel Load Balancing, Layer 3 EtherChannel	0h 57m
9	802.1q Tunneling, Layer 2 Protocol Tunneling, EtherChannel over 802.1q Tunneling	1h 03m
10	STP Root Bridge Election, STP Root Port Election, STP Designated Port Election, STP Priority, STP Cost, STP Port-Priority	1h 46m
11	STP Review	0h 12m
12	STP Timers, STP PortFast	0h 34m
13	STP UplinkFast	0h 11m
14	STP BackboneFast	0h 12m
15	STP BPDU Filter	0h 13m
16	STP BPDU Guard	0h 11m
17	STP Root Guard	0h 11m
18	STP Loop Guard, Unidirectional Link Detection (UDLD)	0h 11m
19	Multiple Spanning-Tree Protocol (MST)	0h 40m
20	Rapid Spanning-Tree Protocol (RSTP), Rapid-PVST	0h 18m
21	MST with Multiple Regions	0h 33m
22	Flex Links	0h 16m
23	Frame Relay	0h 39m
24	Frame Relay Configuration Part 1	0h 34m
25	Frame Relay Configuration Part 2	0h 41m
26	Frame Relay Switching	0h 27m
27	Back-to-Back Frame Relay	0h 08m
28	Frame-Relay End-to-End Keepalives	0h 18m
29	PPP, PPP PAP Authentication, PPP CHAP Authentication	0h 59m
30	PPPoFR, PPPoE	0h 40m
31	Transparent Bridging, IRB	0h 32m
32	Fallback Bridging	0h 14m
33	IP Routing Overview, Switching Paths, Static Routing	0h 42m
34	Static Routing Examples	0h 25m
35	IP Default-Gateway, IP Default-Network	0h 14m
36	On-Demand Routing (ODR)	0h 07m
37	Floating Static Routes	0h 10m
38	Backup Interface	0h 29m
39	Enhanced Object Tracking, IP SLA, Reliable Static Routing	0h 21m
40	Policy Routing	0h 43m
41	GRE Tunneling, GRE Recursive Routing Errors	0h 27m
42	Reliable Backup Interface with GRE	0h 25m
43	RIP Overview, RIP Versions, RIP Auto-Summary	0h 48m
44	RIP Split-Horizon, RIP Timers	0h 22m
45	RIP Broadcast Updates, IP Directed Broadcast, IP Broadcast-Address, Smurf Attacks, Fraggle Attacks	0h 16m
46	RIP Unicast Updates	0h 03m
47	RIP Offset-List	0h 18m
48	RIP Authentication	0h 11m
49	RIP Summarization	0h 10m
50	Prefix-Lists, RIP Distribute-List Filtering, RIP Administrative Distance Filtering	0h 48m
51	RIP Default Routing, RIP Conditional Default Routing	0h 18m
52	RIP Triggered, RIP Validate Update Source,	0h 12m
53	EIGRP Overview	0h 29m
54	EIGRP Auto-Summary	0h 07m
55	EIGRP Split-Horizon	0h 11m
56	EIGRP Update Types, EIGRP Neighbor, EIGRP Passive-Interface	0h 24m
57	EIGRP Hello-Interval, EIGRP Hold-Time	0h 05m
58	EIGRP Authentication	0h 11m
59	EIGRP Time Based Authentication	0h 25m
60	EIGRP Path Selection, EIGRP Metric Weights, EIGRP Traffic Engineering	0h 47m
61	EIGRP Unequal Cost Load Balancing, EIGRP Variance	0h 19m
62	EIGRP QUERY, EIGRP Summarization, EIGRP Leak-Map	0h 28m
63	EIGRP Stub Router Advertisement	0h 22m
64	EIGRP Default Routing	0h 13m
65	EIGRP Route Filtering	0h 11m
66	EIGRP Router-ID	0h 07m
67	Miscellaneous EIGRP Features	0h 02m
68	OSPF Overview	0h 27m
69	Establishing OSPF Adjacencies, Understanding the OSPF Database	0h 43m
70	OSPF Network Type Broadcast, OSPF DR/BDR Election, OSPF over NBMA, OSPF Network Type Non-Broadcast and Point-to-Multipoint	0h 56m
71	OSPF Network Type Point-to-Point, OSPF Network Type Mismatch	0h 13m
72	OSPF Network Type Point-to-Multipoint Non-Broadcast, OSPF Per Neighbor Cost	0h 17m
73	OSPF Network Type Loopback	0h 02m
74	OSPF Path Selection	0h 27m
75	OSPF Convergence Timers	0h 09m
76	OSPF Authentication	0h 12m
77	OSPF Summarization	0h 32m
78	OSPF Stub Areas, OSPF Totally Stubby Areas, OSPF NSSAs, OSPF Totally NSSAs	0h 40m
79	Controlling OSPF NSSA Redistribution	0h 02m
80	OSPF Type 7 to 5 Translator Election, OSPF LSA Type 3 Filter, OSPF Forwarding Address Suppression	0h 24m
81	Route Redistribution Overview	0h 36m
82	Route Redistribution Configuration & Verification, Connected Redistribution	0h 22m
83	OSPF External Path Selection, TCL PING Scripting	0h 33m
84	Routing Loops Overview, EIGRP Route Loop Prevention	0h 55m
85	Metric Based Routing Loops, Route Tagging	0h 46m
86	Administrative Distance Based Routing Loops, Debug IP Routing, IP Route Profile	0h 58m
87	BGP Overview, BGP Peering Types	0h 51m
88	Establishing BGP Peerings, EBGP Multihop, BGP Neighbor Disable Connected Check, BGP TTL Security	0h 49m
89	BGP 4-Byte ASNs	0h 20m
90	BGP Local AS, BGP Peer Groups	0h 30m
91	BGP Next-Hop Self, BGP Next-Hop Processing	0h 30m
92	BGP Route Reflectors	0h 37m
93	Large Scale BGP Route Reflectors with Clusters	0h 34m
94	BGP Confederation	0h 37m
95	BGP NLRI Advertisements, BGP Network Statement, BGP Redistribution	0h 43m
96	BGP Aggregation, BGP Aggregation & Summary-Only, BGP Aggregation & Unsuppress-Map	0h 46m
97	BGP Origin, BGP Aggregation & AS-Set, BGP Aggregation & Advertise-Map	0h 22m
98	BGP Conditional Route Injection	0h 21m
99	BGP Bestpath Selection, BGP Multipath, BGP Weight	0h 53m
100	BGP Local Preference, BGP Local Preference and Communities, BGP AS-Path Prepending,	0h 30m
101	BGP MED, BGP MED Missing As Worst, BGP Deterministic MED	0h 17m
102	BGP Communites, BGP Regular Expressions	0h 43m
103	BGP Filtering, BGP Convergence Timers, BGP Default Routing, Miscellaneous BGP Features	0h 24m
104	MPLS Overview, MPLS Label Distribution Protocol (LDP)	1h 05m
105	MPLS Tunnels, MPLS Penultimate Hop Popping (PHP)	0h 40m
106	MPLS Layer 3 VPNs Overview, VRF Lite	0h 36m
107	MPLS Layer 3 VPNs and VPNv4 BGP	1h 08m
108	MPLS Layer 3 VPN Verification & Troubleshooting	0h 49m
109	MPLS Layer 3 VPN OSPF PE-CE Routing Overview	0h 06m
110	MPLS Layer 3 VPN OSPF PE-CE Routing Path Selection & Sham-Links	2h 01m
111	MPLS Layer 3 VPN OSPF PE-CE Routing Loop Prevention & Down-Bit, OSPF Capability VRF-Lite	0h 40m
112	IPv6 Overview, IPv6 ICMPv6 ND, IPv6 over NBMA	0h 44m
113	IPv6 Routing Overview, IPv6 Static Routing	0h 28m
114	IPv6 RIPng	0h 20m
115	IPv6 EIGRPv6	0h 09m
116	IPv6 OSPFv3	0h 31m
117	MP-BGP for IPv6	0h 26m
118	IPv6 Tunneling	1h 13m
119	Multicast Overview, IGMP	0h 34m
120	PIM Overview	0h 18m
121	PIM Dense Mode	1h 03m
122	PIM Sparse Mode	0h 30m
123	PIM Sparse Mode Configuration	0h 36m
124	PIM Sparse Mode RPF & RP Troubleshooting	0h 27m
125	Auto-RP, Multicast over GRE Tunnels	0h 53m
126	Bootstrap Router (BSR), Bidirectional PIM, Source Specific Multicast (SSM)	0h 40m
127	MSDP, Anycast RP	0h 27m
128	IPv6 Multicast Routing	0h 24m
129	QoS Overview, IntServ QoS, DiffServ QoS, IP Precedence, DSCP, MQC, HQF	0h 41m
130	MQC Classification	0h 44m
131	FIFO, FQ, WFQ, CBWFQ, HQF	0h 50m
132	LLQ	0h 23m
133	WRED	0h 31m
134	Traffic Shaping, Traffic Policing	0h 40m
135	Frame Relay Traffic Shaping (FRTS)	0h 33m
136	RSVP	0h 07m
137	Catalyst 3560 QoS	1h 00m
138	IOS Security Overview, Access Lists (ACLs)	0h 58m
139	Time Based ACLs, Dynamic ACLs	0h 33m
140	Reflexive ACLs	0h 21m
141	TCP Intercept, Content Based Access Control (CBAC)	0h 34m
142	Zone Based Policy Firewall (ZBPF)	1h 09m
143	AAA, Local Authentication, Local Authorization, Role Based CLI Access	0h 43m
144	Port Security, Static CAM Entries, Storm Control, 802.1X Authentication, PACLs, RACLs, VLAN Access Maps (VACLs)	0h 48m
145	DHCP Snooping, Dynamic ARP Inspection (DAI), IP Source Guard	0h 12m
146	Protected Ports, Private VLANs	0h 25m
147	IP Services Overview, HSRP	1h 10m
148	VRRP, GLBP	0h 28m
149	NAT	0h 42m
150	DHCP, DNS	0h 30m
151	NetFlow	0h 09m
152	WCCP, Miscellaneous IP Services	0h 06m
153	System Management Overview, NTP, NTP Authentication	0h 24m
154	SNMP, RMON	0h 38m
155	Syslog, Telnet, SSH, Banners	0h 21m
156	EEM Scripting, Miscellaneous System Management	0h 26m
Total Duration		81h 42m

Slides - Diagrams

Slides - Introduction

Slides - Ethernet Switching

Slides - Advanced Ethernet Switching

Slides - Frame Relay

Slides - PPP

Slides - Transport Bridging

Slides - Redistribution

Slides - IOS Security

Slides - Layer 2 Security

Slides - IP Services

Slides - System Management

0:00:12	So again, with the Split Horizon feature that is
0:00:18	the main interface in frame-relay.
0:00:20	So, if we have a Partial Mesh of frame-relay,
0:00:25	and we are doing a multipoint sub-interface,
0:00:29	then, we would want to disable Split Horizon.
0:00:32	So, in this case, this was on router 5,
0:00:35	where we're using the multipoint sub-interface.
0:00:38	I would then need to go to...
0:00:40	this interface on router 5.
0:00:43	Interface...
0:00:46	s0/0/0.1 and say, or 1.2.3.4 actually.
0:00:55	we should then see on router 2,
0:01:00	that if we Show IP Route RIP,
0:01:06	once router 5's frame-relay interface comes back,
0:01:15	then, we should see that we have all of the routes.
0:01:18	So now, we have all of the loopbacks and all
0:01:22	even though router 5 is sending it in
0:01:27	Now, in reality, it's not really gonna
0:01:32	because the metric is still incremented
0:01:36	So, when router 5 receives the update
0:01:43	the update goes from 1 to 5, then,
0:01:48	If the update had a hop count
0:01:52	then, its gonna have a hop count
0:01:56	So, the metric value still should be used
0:02:03	but with RIP, it's more of an issue
0:02:07	Because we're sending the entire table
0:02:13	We wouldn't wanna be sending all of the
0:02:16	that we know are not gonna be used.
0:02:21	Now, the actual updates themselves...
0:02:24	will depend on what version
0:02:29	Whether we send them as
0:02:32	where RIP version 1 uses the broadcasts by
0:02:38	For RIP version 2, we can change this optionally
0:02:40	under the RIP process, if we say,
0:02:44	That would revert back to
0:02:47	If we were to use the neighbor
0:02:50	then, we would be sending this
0:02:56	Now, this command does differ a little bit
0:03:02	where with RIP, the neighbor statement
0:03:09	but it does not suppress the
0:03:15	So, this means that between
0:03:20	let's say, between router 5 and switch 2,
0:03:25	if I wanna send the updates only as unicasts,
0:03:29	I would need to use the Neighbor
0:03:33	and then also use the Passive Interface command.
0:03:37	So, Passive Interface would block either our...
0:03:42	broadcast or multicast update.
0:03:45	Then, the Neighbor command will
0:03:50	In either case, we can see this by looking
0:03:56	or the Debug IP Packet, and Debug
0:04:00	that's gonna show is where the update
0:04:04	and then, on the other side,
0:04:17	So, let's take a look at this between
0:04:23	If we go to...
0:04:26	router 5, and we look at the Debug IP
0:04:33	What I'm gonna do first is remove the
0:04:38	because I don't wanna see this debug output
0:04:44	So, on all of the routers,
0:04:47	we'll say under router RIP, No Timer's Basic.
0:04:53	So, that's gonna revert us back to our default timers.
0:05:01	Next, on router 5, let's look at the...
0:05:05	Debug IP Packet Detail and Debug IP RIP,
0:05:08	but I'm gonna log this on to the console,
0:05:12	So, I'll say, Logging Console at level 6,
0:05:17	which is everything except debug messages.
0:05:19	And I wanna log to the buffer at level 7.
0:05:24	Also, I'll set the buffer size to be very large...
0:05:28	to make sure that we're not gonna
0:05:35	So now, I'll say, Debug IP Packet
0:05:41	At this point, if we look at the Show Log,
0:05:44	we should see the default updating
0:05:50	where the version 1 packets are being
0:05:57	where the version 2 updates are
0:06:03	Now, remember, this link Fast Ethernet 0/1, I set it
0:06:10	So, it's sending separate versions out there.
0:06:13	The version 1 update is including
0:06:19	plus the subnets that match the
0:06:24	or in this case, that 155.10.88.88,
0:06:35	Then, we could see the RIP version 2,
0:06:40	And then, we would also see that we are receiving
0:06:47	Okay, if we look at this again, we should
0:06:53	From Debug IP Packet Detail.
0:06:57	This shows us that the version 1 packet
0:07:05	With UDP source 520 and destination 520.
0:07:09	Whereas the multicast update goes to 224.0.0.9.
0:07:13	Both again the the source and destination
0:07:20	Now, if we were to change this,
0:07:24	on router 5,
0:07:26	let's say on the link to switch...
0:07:32	The link to switch 2, which is Fast Ethernet 0/0.
0:07:37	I'll say, IP RIP V2 Broadcast.
0:07:43	So now, if we say, Show Log,
0:07:48	and Begin Fast Ethernet 0/0,
0:07:53	we should see and... Let's clear the log out.
0:08:03	We should see now that next time
0:08:09	this is gonna go to the...
0:08:15	the all subnet broadcast.
0:08:46	So now, we can see, only... Or even
0:08:50	now, this is sent as a broadcast to
0:08:56	Now, the interface level...
0:09:00	also supports a directed broadcast address.
0:09:03	If we were to look at the Show IP Interface,
0:09:08	Show IP Interface Fast Ethernet 0/0,
0:09:12	it says that "The broadcast address...
0:09:15	by default is the...
0:09:17	is the all host broadcast address."
0:09:22	Now, the directed broadcast address of the link would be
0:09:31	So, in the case of a /24, it's gonna be the first
0:09:38	So, 155.10.58.255 would be the
0:09:44	Normally, directed broadcasting is disabled,
0:09:48	because there's a lot of security
0:09:53	We'll see later in the security section,
0:09:56	the Smurf Attack that use the directed broadcast
0:10:06	but technically, you can enable this.
0:10:08	If I were to go to the link level, and say
0:10:14	and the IP broadcast address
0:10:19	So, 155.10.58.255.
0:10:24	This would then mean, when I am
0:10:29	I would be sending them to
0:10:34	So, if we say, Show Log and begin...
0:10:38	this address.
0:10:42	We could see now that the updates
0:10:49	So, it's kind of a stupid router trick. There's really
0:10:53	But you could control whatever address that
0:11:00	by changing the update to a version 2 broadcast,
0:11:04	enabling directed broadcast and then changing with
0:11:11	So, if we look at the Show Run
0:11:16	this is turning the all host broadcast
0:11:22	This is then changing what
0:11:27	and allowing us to send directed
0:11:31	Now, the reason why you would
0:11:34	is it means devices on remote segments can
0:11:43	So, if I were to go to...
0:11:47	Let's say switch 3.
0:11:49	And I send a packet out now
0:11:57	it actually allows me to route the
0:12:01	and then, drop if off as a broadcast...
0:12:05	on this link.'
0:12:08	So, from switch 3, if I simply...
0:12:12	ping 155.10.58.255,
0:12:20	and let's look at the Debug IP ICMP.
0:12:28	Notice that I got replies back from
0:12:36	So, for every one packet that I sent out,
0:12:40	I get a response from every
0:12:45	Now, where this would be used from
0:12:50	is that switch 3 could be configured
0:12:56	where the source address is the victim,
0:13:00	and the destination address is a directed broadcast.
0:13:04	So, let's say theoretically, that I wanna
0:13:12	So, on switch 3, what I could do is...
0:13:15	create a loopback that matches
0:13:19	Let's say I configure this as 150...
0:13:31	Actually, let's do it this way. On router 2...
0:13:35	I'm gonna advertise this link as well.
0:13:43	Then, on switch 3, I'm gonna configure
0:13:54	So, it's basically the address that router 2
0:13:58	Then, if switch 3 source
0:14:03	with the destination of the directed
0:14:10	it means that when the host
0:14:15	they're gonna route the
0:14:23	So first, let's go to router 2...
0:14:26	And under the RIP Process, I'm going to
0:14:35	This should then mean that everyone in
0:14:39	If I ping 192.10.10.2,
0:14:43	we have reachability to router 2's address.
0:14:46	Now, on switch 3 who is the attacker,
0:14:49	I'll say, Interface Loopback 192.
0:14:53	Has an address of 192.10.10.2...
0:14:58	/32.
0:15:01	I'm now going to..
0:15:05	send pings that go
0:15:11	of that VLAN 58,
0:15:14	but I'm sourcing them from this new loopback...
0:15:18	with a...
0:15:20	High repeat count.
0:15:22	And a time out of zero.
0:15:24	So, it's basically just sending the packets
0:15:30	Now, if I go to router 2,
0:15:33	and, I'll do this on the buffer.
0:15:38	Logging Buffer 7.
0:15:39	And then, we Debug IP ICMP.
0:15:43	If we look at the log,
0:15:50	all of these echo replies, these are coming in
0:15:57	So, for every one echo that switch 3 is sending,
0:16:01	router 2 who is the victim in this
0:16:09	So normally, this attack is not viable, because
0:16:15	This is the reason that you should not enable it.
0:16:19	Okay, there's some real minor features we'll see
0:16:24	when you would have to turn directed broadcast on.
0:16:26	But in production, you're not gonna want to use those.
0:16:30	Because it's too easy of an attack to implement,
0:16:36	which is the Smurf Attack, it's called.
0:16:41	UDP versus ICMP, they have two different names.
0:16:45	Smurf and Fraggle.
0:16:47	I'm not sure, on of them is ICMP; one of
0:16:51	But they both use the same logic that they're
0:16:57	by going to the directed broadcast address.
0:17:03	So again, on router 5 here, it's kind of a stupid router trick,

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CCIE R&S Advanced Technologies Class v4.5
Title:	CCIE R&S Advanced Technologies Class v4.5
Duration:	81h 42m
The CCIE Routing & Switching Advanced Technologies Class is the first step in understanding CCIE level technologies and is a companion to the Advanced Technologies Lab Workbook. Each technology you need to know for the CCIE Routing & Switching lab will be described in detail using an instructor led hands on demonstration. The class consists of over 80 hours of in depth explanations and examples.
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