Minor Stack Protocol Version Number Incompatibility Among Stack-Capable Switches

Minor Stack Protocol Version Number Incompatibility Among Stack-Capable Switches


Switches with the same major version number but with a different minor version number are considered partially compatible. When connected to a switch stack, a partially compatible switch enters version-mismatch (VM) mode and cannot join the stack as a fully functioning member. The software detects the mismatched software and tries to upgrade (or downgrade) the switch in VM mode with the switch stack image or with a tar file image from the switch stack flash memory. The software uses the automatic upgrade (auto-upgrade) and the automatic advise (auto-advise) features.

The port LEDs on switches in version-mismatch mode will also remain off. Pressing the Mode button does not change the LED mode.

OSPFv2 and OSPFv3 headers

#DoYouKnow #OSFP #Routing

All OSPFv2 packets have a common 24-byte header, and OSPFv3 packets have a common 16-byte header, that contains all information necessary to determine whether OSPF should accept the packet. The header consists of the following fields:

• Version number—The current OSPF version number. This can be either 2 or 3.
• Type—Type of OSPF packet.
• Packet length—Length of the packet, in bytes, including the header.
• Router ID—IP address of the router from which the packet originated.
• Area ID—Identifier of the area in which the packet is traveling. Each OSPF packet is associated with a single area. Packets traveling over a virtual link are labeled with the backbone area ID, 0.0.0.0. .
• Checksum—Fletcher checksum.
• Authentication—(OSPFv2 only) Authentication scheme and authentication information.
• Instance ID—(OSPFv3 only) Identifier used when there are multiple OSPFv3 realms configured on a link.

Cisco router load balancing and CEF (Cisco Express Forwarding)

#DoYouKnow #CiscoTips #Cisco

Per-destination or per-packet load-balancing depends on the type of switching scheme used for IP packets. By default, on most Cisco routers, fast switching is enabled under interfaces. This is a demand caching scheme that does per-destination load-balancing. To set per-packet load-balancing, enable process switching (or disable fast switching), use these commands:

Router(config-if)# no ip route-cache

Now the router CPU looks at every single packet and load balances on the number of routes in the routing table for the destination. This can crash a low-end router because the CPU must do all the processing.

Newer switching schemes such as Cisco Express Forwarding (CEF) allow you to do per-packet and per-destination load-balancing more quickly. However, it does imply that you have the extra resources to deal with maintaining CEF entries and adjacencies.

When you work with CEF, you could ask: Who does the load balancing, CEF or the routing protocol used? The way in which CEF works is that CEF does the switching of the packet based on the routing table which is being populated by the routing protocols.

I like cef...

#Extra tips for my blog readers:

, CEF performs the load-balancing once the routing protocol table is calculated.

Block "Botnet and Control & Command Servers" on Fortigate

Are you making same "big" mistake in Fortigate firewall configuration?  Are you blocking "Botnet & C&C Servers"? He (My friend, Security Implementation Engineer) is unaware or ignoring about configuration changes onward Forti OS 5.4. This is called "Scan Outgoing Connections to Botnet Sites".  Previously it was (5.2)  "Detect Connections to Botnet C&C Servers" in Security Profiles -> AntiVirus. but today this is available "Scan Outgoing Connections to Botnet Sites"  in Network->Interfaces->Edit Interface (WAN).  #securities #Fortigate #fortinet #securityawareness #DoYouKnow

Multicast OSPF LSA (Type 6) on Cisco router

Cisco routers do not support LSA Type 6 Multicast OSPF (MOSPF), and they generate syslog messages if they receive such packets. If the router is receiving many MOSPF packets, you might want to configure the router to ignore the packets and thus prevent a large number of syslog messages.


Commands:
#Router ospf 0.0.0.1
#ignore lsa mospf

Does ospf having backup path?

 OSPF uses the SPF algorithm. The information contained in a router’s OSPF link state database is the “MAP” that is used to calculate the best path to a remote network. However, unlike EIGRP, OSPF does not keep backup paths to routes, rather, when a route to a network goes down, the SPF algorithm is run again to determine a backup or alternate path.
Keep in mind no backup link.. if there are any dual active paths to any destination with same metric then load balancing will work (default up to 4 Path).

What Do We Mean by Link-States?

What Do We Mean by Link-States?

OSPF is a link-state protocol. We could think of a link as being an interface on the router. The state of the link is a description of that interface and of its relationship to its neighboring routers. A description of the interface would include, for example, the IP address of the interface, the mask, the type of network it is connected to, the routers connected to that network and so on. The collection of all these link-states would form a link-state database.

OSPF LSA in Details

Somedays before (last year), I have published a post about the OSPF LSAs types and definitions. Today I am going to share some more details about the SLAs as which router will generate the which LSAs:

1. 

SLA Name: Router LSA 

Link-State ID: Originating router ID of the router

Generated By: Router LSAs are generated by every router. 

2. 

SLA Name: Network LSA 

Link-State ID: Interface IP address of the DR

Generated By: Network LSAs are generated by the DR on a multi-access segment. They are the representation of the multi-access segment and all the routers attached to the segment. Segments that do not have a DR, such as point-to-point, will not have a network LSA.

3.

SLA Name: Network summary LSA

Link-State ID: Destination network number

Generated By: Network summary LSAs are generated by ABRs. 

4.

SLA Name: ASBR summary LSA

Link-State ID: Router ID of AS boundary router

Generated By: ASBR summary LSAs are also generated by the ABR. This LSA describes the location of an ASBR, not a network. 

5. 

SLA Name: AS external LSA

Link-State ID: External network number

Generated By: Autonomous System (AS) External LSAs are originated by the ASBRs and describe a network outside of the AS.

7. 

SLA Name: NSSA external LSA
Link-State ID: External network number
Generated By: Not-So-Stubby Area (NSSA) external LSAs are originated by the ASBR within the NSSA. These types of LSAs are flooded only throughout the NSSA.

I hope it will very helpful for you!

OSPF Tips - Summarization of Network

#CiscoTips #OSPF #DoYouKnow

An internal summary route is generated if at least one subnet within the area falls in the summary address range and the summarized route metric is equal to the lowest cost of all the subnets within the summary address range. Interarea summarization can only be done for the intra-area routes of connected areas, and the ABR creates a route to Null0 to avoid loops in the absence of more specific routes.

OSPF network planning tips - Summarization of network

#CiscoTips #DoYouKnow #OSPF #Design Summarization design is a process of network planning: One step fails, Network fail::: If the OSPF design includes many ABRs or ASBRs, suboptimal routing is possible. This is one of the drawbacks of summarization. Route summarization requires a good addressing plan—an assignment of subnets and addresses that are based on the OSPF area structure and lends itself to aggregation at the OSPF area borders.

FortiOS is having a site to site VPN replacement

#FortiTips #Tips #DoYouKnow
FortiOS is having a site to site VPN replacement Don't worry. This is a cool feature. FortiOS WAN optimization supports secure SSL-encrypted tunnels between FortiGate units on the WAN. Employing secure WAN Optimization tunnels can replace IPsec VPNs between sites. The result is a single, relatively simple configuration that supports optimization and privacy of communication across the WAN and uses FortiGate SSL acceleration to provide high performance.

OSPF LSA Types

OSPF uses a LSDB (link state database) and fills this with LSAs (link state advertisement).

Here Some details about all SLA types:-

• LSA Type 1 (Router LSA)

Router Link State Advertisements Type 1 are generated by every router for each link that belongs to an area. They are flooded only inside of area to which they belong. Link ID of this LSA is the Router ID of the router that generated it.

• LSA Type 2 (Network LSA)

Generated by Designated Router (DR) for multiaccess networks and describe the routers that are connected to that segment. They are sent inside the area to which the network segment belong.

• LSA Type 3 (Summary LSA)

Type 3 LSAs are generated by Area Border Routers (ABRs). In type 3 LSAs are advertised networks from an area to the rest of the areas in AS. Advertised networks in Type 4 LSA can be summarized or not. The link-state id used by this LSA is the network number advertised.

• LSA Type 4 (ASBR Summary LSA)

Generated by ABRs, this type of LSA contain routes to ASBRs. Link id used is router ID of the ASBR described. Are not flooded in stub areas.

• LSA Type 5 (External LSA)

Autonomous system external LSAs are generated by ASBRs and contain routes to networks that are external to current AS. Link-state ID is network number advertised in LSA. Type 5 LSAs are not flooded inside any stub areas.

• LSA Type 6 (Multicast LSA)

This type of LSA is used for multicast applications. Not supported on Cisco.

• LSA Type 7 (NSSA External LSA)

Type 7 LSA allow injection of external routes through Not-so-Stubby-Areas (NSSA). Generally external routes are advertised by type 5 LSA but they are not allowed inside any stub area.
 Type 7 LSA is generated by NSSA ASBR and is translated into type 5 LSA as it leaves the area by NSSA ABR, which is then propagated throughout the network as type 5 LSA.

• LSA Type 8 (External LSA for BGP)

Used to work with BGP.

• LSA Type 9,10,11 (Opaque LSAs)

Cisco CDP protocol tutorial, configuration with examples

CDP, Cisco Discovery Protocol Configuration and guide

Cisco CDP ducoment by deepak kumar from Deepak Kumar

RIP (Routing Information Protocol) Version 2

Configuration of RIP (Routing Information Protocol) Version 2.

Rip 2 docoments version 1.1 by deepak kumar from Deepak Kumar

Technical difference between Router and Layer 3 (L3) Switch

What is Technical difference between Router and Layer 3 (L3) Switch ?

 What is Packet Switching difference between Router and Layer 3 Switch ?

Do you know that Router and L3 Switch are both L3 Devices ?.. Lets start Reading in panel.

Router vs layer 3 switch from Deepak Kumar

RIP "Routing Information Protocol" guide Document Version 1

RIP Protocol "Document Version 1" from Deepak Kumar

Everything about RIP Protocol with downloadable file. Enjoy and Read. 

Cisco Real Time Configurations‏ - OSPF on L3 Switches

Dear Friends,

Today is my first series on Cisco Real Time Configuration.

Now you can Download PKT and Test on your system.

Today Topic -  OSPF Configuration on L3 Switch (Routing).

I hope you will like it.

Note -  Your Comments are very important for me.

Download:- Download Packet Tracer Real Time Configuration .. OSPF Routing on L3 Switch.

Devices User Name -  deepak
Devices Password - deepak

Click on Download Option for save it on your computer.

Pak hackers target Indian Gmail users

A Media Report says that Pakisthan Hacker target the Indian Gmail Users with Fake Email Login Page, Which is hosted in Karachi (Pakisthan). About 160 Person has reported under the IT act.

" Pakistani cyber criminals now have their eyes fixed on the Gmail accounts of Indian users. The hackers have created a page that looks extremely similar to that of Gmail and they are using this page to break into the accounts of the Indian users. The page looks so similar to that of Gmail home page that it is very difficult for the users to notice the minor differences and thus they fall in the trap laid out by the Pakistani cyber criminals. 

 

When Bhaskar group investigated the matter it was revealed that the group of hackers based in Karachi have hacked into hundreds of accounts of the Indian businessmen and caused them a loss running into crores. 

 

'Special sign-in prevented'

 

Gmail users in India have been getting an email, the subject of which says ‘special sign-in prevented’ and the email of the sender is no-reply@gogle.account.ca, the hackers have created an app which can be used to sign in to your account. The mail besides showing the time of the mail sent and the person’s name also reflects the location and IP address. To track the user a button has been inserted in the mail which says ‘sign-in activities’.

  
The domain traced back to Pakistan

 

According to cyber experts domain www.sumsumbuilders.com can be traced back to Pakistan and has been registered under the name of Altan Janu, this domain has been hosted on hostingkarachi.com. If a user enters his id and password in this domain then the information can be accessed by the cyber criminals.
 
160 cases of hacking registered under IT act

 

According to the data 160 cases have been registered under the IT act with the Jodhpur commissionerate, Out of these cases 48 have been referred to  FR as the police is not equipped and trained to handle cyber crime. In March 2014, a resident of Jaipur had registered a case of cyber crime in which Rs 30 lakh had been withdrawn from his account. Number of such cases have been registered with the police. " @Daily Bhaskar

Here I am Sharing Some Tips to secure your account..
1. Always Make Sure That URL is same as you type in address bar.
2. Google Never Used Self Certificate for SSL.
3. Never Give Permission to Untrust Self Certificate
4. Make Sure That You have a Green Pandle in Address Bar.
5. Make Sure that you have "https://..." in starting of your URL.
6. Always Make Sure that which Organization Issued the SSL Certification and Which Organization used it. You have the same name in Issued to filed, which is you have typed the URL in Address Bar.

Here I posted the a screen shot for an example

Fake & Real Page Of Gmail Login Page - 

SSL Certificate Test -

Your Account Security & Privacy is your right. Stay Safe & Updated. 

I am Back

Hello Friends,

After A long time absent I am coming back here, Now I will write regular post.

Regards,
Deepak

Secure your WordPress Website

I know you are aware about online security and maintain security policy. Today I am writing about WordPress security. I hope you are using WordPress with your website or WordPress on wordpress.com. A person who is scanning your WordPress week point and take control on your blog, is called hacker and your WordPress hacked.

Wordfence is a WordPress plugin for maintain security, Real time scanning, firewall, geolocation and cyber security. This is offer many features for free and payed user. It is offering following features.

• Cellphone Sign-in
• Remote Scans
• Country Blocking
• Frequent Scans
• Scheduled Scans

Read More >>>