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Packet Captures

UDLD.cap 3.3 KB

Submitted Sep 14, 2009

Unidirectional Link Detection (UDLD) is used to monitor the status of a link between a Catalyst 2960 and a Catalyst 3560. Note that echos are initially sent at very small intervals, gradually throttling back to the configured interval of 15 seconds.

Ethernet LLC UDLD

Packets: 29 Duration: 93s Downloads: 6278

TDP.cap 2.8 KB

Submitted Sep 14, 2009

P2 and PE2 exchange Tag Distribution Protocol hellos and form an adjacency over TCP port 711.

Ethernet IP TCP TDP UDP

Packets: 33 Duration: 47s Downloads: 4273

HSRP_failover.cap 3.0 KB

Submitted Sep 14, 2009

R1 is the active router, R3 is the standby, and R2 is passive. R1 goes offline and R3 takes over as active after ten seconds. R2 is then promoted to the standby state.

Ethernet HSRP IP UDP

Packets: 39 Duration: 47s Downloads: 4759

HSRP_election.cap 3.7 KB

Submitted Sep 14, 2009

The Ethernet link shared by routers 1, 2, and 3 comes online. R1 wins the HSRP election because it has a priority of 200 (versus the default of 100 held by the other two routers). R3 becomes the standby router.

Ethernet HSRP IP UDP

Packets: 49 Duration: 57s Downloads: 4421

HSRP_coup.cap 3.9 KB

Submitted Sep 14, 2009

Initially only routers 3 (active) and 2 (standby) are online. R1 comes online with a priority higher than R3's. R1 takes over as the active router (the coup occurs in packet #22) almost immediately. R2 is bumped down to passive and R3 becomes the standby router.

Ethernet HSRP IP UDP

Packets: 51 Duration: 49s Downloads: 3971

HDLC.cap 3.4 KB

Submitted Sep 14, 2009

ICMP across an HDLC serial link.

CDP HDLC ICMP IP SLARP

Packets: 38 Duration: 111s Downloads: 4292

EIGRP_subnet_up.cap 1.3 KB

Submitted Sep 14, 2009

R4's 192.168.4.0/24 subnet is brought online. R1 receives updates from both R2 and R3 (only R2's update is shown in the capture). The poison-reverse in packet #9 informs R2 not to use R1 as a path to 192.168.4.0/24. The capture perspective is from R1's 10.0.0.1 interface.

EIGRP Ethernet IP

Packets: 15 Duration: 18s Downloads: 5242

EIGRP_subnet_down.cap 1.8 KB

Submitted Sep 14, 2009

R4's interface to 192.168.4.0/24 goes down and the route is advertised as unreachable. Queries are issued by all routers to find a new path to the subnet but none exists, and the route is removed from the topology. Capture perspective is from R1's 10.0.0.1 interface.

EIGRP Ethernet IP

Packets: 21 Duration: 23s Downloads: 3901

EIGRP_goodbye.cap 1.3 KB

Submitted Sep 14, 2009

R2 designates its interface facing R1 as passive. The final hello message from R2 (packet #9) has all its K values set to 255, designating the message as a "goodbye." Capture perspective is from R1's 10.0.0.1 interface.

EIGRP Ethernet IP

Packets: 15 Duration: 43s Downloads: 4642

EIGRP_adjacency.cap 5.1 KB

Submitted Sep 14, 2009

Formation of an EIGRP adjacency between routers R1 and R2. Capture point is R1's 10.0.0.1 interface.

EIGRP Ethernet IP

Packets: 53 Duration: 104s Downloads: 5727

EIGRPv2_subnet_transition.cap 5.3 KB

Submitted Sep 14, 2009

R4's 2001:db8:0:400::/64 subnet goes down, then comes back up roughly thirty seconds later. Capture perspective from R1's 2001:db8:0:12::1 interface.

EIGRP Ethernet IPv6

Packets: 49 Duration: 65s Downloads: 4028

EIGRPv2_adjacency.cap 4.1 KB

Submitted Sep 14, 2009

Routers 1 and 2 form an EIGRPv2 adjacency and exchange IPv6 routes.

EIGRP Ethernet IPv6

Packets: 31 Duration: 52s Downloads: 4224

DTP.cap 934 bytes

Submitted Sep 14, 2009

Dynamic Trunking Protocol (DTP) emanated from a Catalyst 3560 every 60 seconds, both with and without ISL encapsulation.

DTP Ethernet ISL LLC

Packets: 10 Duration: 120s Downloads: 5280

3725_CDP.cap 390 bytes

Submitted Sep 14, 2009

Cisco Discovery Protocol (CDP) from FastEthernet0/0 of a Cisco 3725 router.

CDP Ethernet LLC

Packets: 1 Duration: n/a Downloads: 4206

3560_CDP.cap 1.2 KB

Submitted Sep 14, 2009

Cisco Discovery Protocol (CDP) advertisements from a Catalyst 3560. Note how much information is offered to a potential attacker.

CDP Ethernet LLC

Packets: 3 Duration: 120s Downloads: 4739