If there are multiple EIGRP and OSPF neighborship flap over the GRE tunnel what could be the problem and how would solve it?

If in the logging you are getting the error message %TUN-5-RECURDOWN: Tunnel0 temporarily disabled due to recursive routing It means that GRE Router tunnel has found a recursive routing problem. The symptoms of this issue include the continous flapping of tunnel interface as well as EIGRP,OSPF & BGP neighbours when neighbours are over the GRE. [...]

How to configure ACLs that permit only established connections and deny all traffic sourced from the external network

Adding the established keyword at the end of access-list indicates that packets belong to an existing connection if the Transmission Control Protocol (TCP) datagram has the Acknowledgment (ACK) or Reset (RST) bit set. access-list 110 permit tcp any any established When you add this make sure you enable DNS otherwise the url will not able [...]

What are the types of BGP Routing table?

There are three types of BGP Routing tables: a) Adj-RIB-in b) Adj-RIB-out c) Loc-RIB Adj-RIB-in stores the unprocessed information received from its peers. Here the best path selection occurs as per BGP attributes and after conformation path is entered into the local bgp table i.e Loc-RIB. From the local RIB table it conform the next-hop [...]

What are the advantages of EIGRP?

EIGRP uses AS (Autonomous system) number ranging from 1-65535 to identify collection of routers that share same information. EIGRP have less convergent time and is more efficient EIGRP supports both auto and manual route summarization Supports multiple routed protocols like IP ,IPX and apple talks EIGRP converges rapidly in the event of link failure EIGRP [...]

How to configure the Sup engine redundancy in the Cisco 6500?

To set up the SUP engine redundancy one must have the same version of iOS. Once Sup engine redundancy is configured one switch will act as Active Sup and the other will act as standby sup engine Cisco6500(config)# redundancy Cisco6500(config-red)#keepalive-enable Cisco6500(config-red)#mode sso Cisco6500(config-red)#main-cpu Cisco6500(config-red-main-cpu)#auto-sync running-config SSO (Stateful Switch over) mode means it will sync the [...]

What is TCP Window Size?

TCP is a connection-oriented protocol both ends of a connection keep strict track of all data transmitted, so that any lost or jumbled segments can be retransmitted or reordered as necessary to maintain reliable transport. To compensate for limited buffer space (where received data is temporarily stored until the appropriate application can process it), TCP [...]

What is BPDU

BPDU’s are the messages exchanged between switches to calculate the spanning tree topology.Bridge Protocol Data Units (BPDU’s) frames contain information regarding the Switch ID, originating switch port, MAC address, switch port priority, switch port cost etc. Bridge Protocol Data Units (BPDU’s) frames are sent out as multicast messages regularly at multicast destination MAC address 01:80:c2:00:00:00. [...]

What will happen if two switch are connected to each other by two cables and spanning tree is disabled?

When a redundant connection is made, we will start receiving MAC address flapping notifications such as %SW_MATM-4-MACFLAP_NOTIF: Host 003b.20c2.0264 in vlan 1 is flapping between port Fa0/4 and port Fa0/5 These are triggered by the never-ending broadcast storm initiated by every layer two broadcast (such as an ARP request) from any host on the VLAN. [...]