In this question I can easily see why a and c are using eBGP. However, why is b and d iBGP instead of OSPF and RIP respectively?
Thanks
Edit: This is an excerpt from Computer Networking by Kurose and Ross.
This should answer all your questions.
This is a horrendous example, because it doesn't detail which nodes are actually speaking iBGP ( nor the 'why' ), but the reason b and d get the information from iBGP is because the prefix has no method to make it into the IGP. This could change easily though if you configured the EBGP speaking nodes to redistribute the eBGP learned routes into their respective IGPs ( OSPF and RIP respectively )
Related
I am currently trying to build an easy TCP structure in C, following the OSI model,
And I just found that there are 2 differents type of "ether" use no kernel related, which are using similar struct,
I guess the "if_ether.h" intervene if a L2 layer does not exist ?
Or an address is not set.
While the "ether.h" is there to configure directly if a use of the L2 is done.
Or is it something who intervene in case of protocol like "PPP", or anything who may bypass the L2 like a Rawsocket
Some stuff are blur.
Thank you in advance to share your light with me.
Take care !
I am curently looking for a dictionary that contains all (or a lot) of interfaces names for routers and switches.
For instance a dictionary that would look like this :
[[Cisco : GigabithEthernet1/0/0, ..., GigabithEthernet1/0/28, FastEthernet1/0/0, ...],
[Juniper : ge-0/0/1, ..., ge-0/0/12,fa-0/0/1, ...,fa-0/0/12]]
I would like it to contain as much of interfaces names of as much of brand as possible.
I have already been looking for it for a long time now, but I have not been able to find anything so far. So if anyone has something to share on this it would be very much appreciated.
Thanks for reading.
A quick update to inform you that I have not been able to find a dictionnary and that after some research I find out that you don't need one if your problem is to identify interfaces on a switch or router.
Using SNMP, you can find which one of the interfaces on your machine is a physical or logical interface. So I used this reference to know which one of my interfaces are physical interfaces or not.
The OID is : 1.3.6.1.2.1.2.2.1.3
Thanks for the help I have been given so far !
I've seen around IPv4 subnet address ranges expressed in a compact form.
For example:
127/24 == 127.0.0.0/24
10/8 == 10.0.0.0/8
10.10.10/24 == 10.10.10.0/24
BTW I can't find any RFC (or any other kind of official or semi-official documentation) that describes it.
Does anyone have some links to share?
I recall this notation being used on Juniper routers as far back as 2001; not sure what, if any, RFC defined it. RFCs do not define the whole planet; somehow over the years they replaced specifications (which are/were much more detailed), but were originally intended for Request For Comments. (Gee, I wonder why there are so many bugs in networking gear.)
I took a look over the already asked questions and I didn't find the information I need. In case I miss the questions somehow, please accept my apologize.
I would like to know how can I use a router as switch on GNS3? Since GNS3 (at least in this moment) doesn't accept switches images, how can it be done?
Once this step is made, it is possible to use most the important switch functions? like etherchannel, trunk, multiple vlans etc.
Thank you very much.
Firstly, there is no true way to put switching into hardware, as of yet, that is. The TCAM's functions in L3 switches these days has yet to be perfected in software.
Secondly, there are a couple of ways to do this, but out of the three, two of them will either cost money or take some investigative work.
Drag the switch icon into the simulation. You can do vlan tagging as an access port, or as a trunk port. No etherchannel though. Alternatively, the 3725 Router has some switching capabilities using the 16-ESW card, however functionality is limited and syntax differs.
Buy VIRL from Cisco's website. It is basically an Ubuntu VM with Cisco routers, IOSvL2 (a switch essentially), ASAv, and a couple other virtual network devices. However, if you're not a student, it's a few bucks. In addition, it is subscription based
3.Upload IOU to GNS3. You will need:
-IOU image, found here: http://sourceforge.net/projects/gns-3/files/IOU%20VMs/
-Virtualbox
-License file for IOU
-GNS3 (Obviously)
-L2/L3 IOU images (The L2 images are switches)
You can find the instructions here: http://srijit.com/how-to-configure-iou-in-gns3-for-real-cisco-switching-labs/
Hope this helps.
I want the equivalent online resource to DNS in Twenty-One Days. I need one evening's reading that will explain what the different record types do, how do propagation and caching work, what is an SoA, etc.
I don't want anything that begins by explaining what DNS is.
Can anybody please point me in the right direction to find some online 'DNS for Geniuses' guide, please?
Check out DNS for Rocket Scientists
It does start with a very brief "What DNS is" but you can easily skip that.
You can also check out Records 101 which gives a good overview of the different record types - the examples are specific to DNSMadeEasy though.
I keep DNS and BIND on my bedside table. It was good to get me going (I used the TOC and skipped the "What is DNS" bits), and it keeps on giving me confidence and a helping hand.
I don't normally buy soot-on-dead-trees books, but this one is a rare exception that has repaid me many times over.
The definitive source, and quite readable (IMO):
http://www.ietf.org/rfc/rfc1035.txt
When I set up DNS for the first time I read DNS HOWTO. It worked pretty well for me.