If a TCP connection does not complete the three-way handshake within a particular time period, TCP intercept sends a TCP reset to the server, cleaning up the connection.
Which TCP intercept mode does this statement best describe?
Highlight for answer: Watch mode.
By default, when does a Cisco router switch over from the root-path-tree to the source-specific SPT?
Highlight for answer: When the first packet is received from the shared tree. You can change this with the ‘ip pim spt-threshold’ command.
A port in the Spanning Tree state of ‘blocking’ does not allow any type of traffic – true or false?
Highlight for answer: False – BPDUs are still allowed over the link.
Does an OSFP stub explicitly filter Type-4 LSAs, or is their absence in an OSPF stub area simply due to being unnecessary because the Type-5 LSAs have been filtered?
Highlight for answer: Actually, I don’t know the answer to this question. I was thinking about it today. In an OSFP stub area Type-5 LSAs are explicitly filtered. There are no Type-4 LSAs present either. I don’t know if they are explicitly filtered, or they are just never generated because the Type 5 LSA is filtered/never created? It’s my understanding (possibly a misunderstanding) that the ASBR generates the Type-4 LSA, so…it must be explicity filtered at the ABR, right? <–This is WRONG!🙂
Thank you for the comments (big ups to Ivan P, Zeeshan, and Pavel Sefanov). I think that I have this cleared up in my head now:
The ABR generates the Type-4 LSA. If the area is configured as a stub area, the ABR filters the Type-5 LSAs(generated by the ASBR) and does not generate a Type-4 LSA. So, technically, an OSPF stub configuration only explicitly filters Type-5 LSAs, but it implicitly filters Type-4 LSAs as well as there is no need for the ABR to generate a Type-4 LSA.
So if you were to tell a co-worker that both Type-5 and Type-4 LSAs are filtered, you would be technically wrong. 😦
Ivan Pepelnjak from Cisco IOS Hints and Tricks wrapped it up nicely:
To make it more explicit: the type-4 LSA is the glue that ties together a type-5 LSA originated by an out-of-area ASBR with the ABR flooding type-5 into the area. If there are no type-5 LSAs, type-4 LSAs are not needed (you will also not see them for ASBRs in the same area).
What are the two tables that CEF utilizes to switch packets?
Highlight for answer: Forwarding Information Base(FIB) and [CEF] adjacency table.
What are the three tables that EIGRP uses?
Highlight for answer: EIGRP neighbor table, EIGRP topology table, and the IP routing table.
Which Spanning Tree convergence improvement utilizes Root Link Query (RLQ) BPDUs to detect indirect link failures?
Highlight for answer: BackboneFast
Which Cisco-supported PIM mode uses shared trees?
Highlight for answer: PIM Spare Mode (also PIM Sparse-Dense mode)
What is the effect of issuing the exec level command ‘terminal monitor’?
Highlight for answer: This command will enable the device to send log messages to telnet sessions.
What are unsolicited messages sent from an SNMP agent to an SNMP management station called?
Highlight for answer: SNMP traps. SNMP informs fit this description as well.