ccie devnet sdn Python, REST APIs, JSON, XML, Linux Skills, Ansible, puppet, chef, github, docker, NETCONF/YANG, NFVs Enterprise Load Sharing L2 (VLAN) design, vxlan, geneve, NVGRE, vPCs, multichassis etherchannel pagp lacp, VSS, L2 WAN PPP chap over ethernet OSPF MP-BGP EVPN MPLS VRF VPN Tunneling DMVPN, Advanced Routing Policies, Advanced IGP & BGP High Availability Cisco sales knowledge, backplane, Distributed / Centralized Control Plane, Data Plane Traffic Enginnering

Jorge Arredondo Dorantes

Jorge Arredondo Dorantes

How do prefix-list works? what is a prefix -list? all you need to know about prefix-list with examples

The truth about prefix-lists.
 How it works? what is a prefix -list? prefix-list examples

Hey guys, remember prefix-lists are used to match on prefix and prefix-length pairs. Normal prefix-list syntax is as follows:
ip prefix-list LIST permit w.x.y.z/len
Where w.x.y.z is your exact prefix
And where len is your exact prefix-length
“ip prefix-list LIST permit! would be an exact match for the prefix
with a subnet mask of This does not match, nor does it match, nor anything in between.

When you add the keywords “GE” and “LE” to the prefix-list, the “len” value changes its
meaning. When using GE and LE, the len value specifies how many bits of the prefix you
are checking, starting with the most significant bit.

ip prefix-list LIST permit le 32
This means:
Check the first 24 bits of the prefix
The subnet mask must be less than or equal to 32
This equates to the access-list syntax:
access-list 1 permit

ip prefix-list LIST permit le 32
This means:
Check the first 0 bits of the prefix
The subnet mask must be less than or equal to 32
This equates to anything

ip prefix-list LIST permit
This means:
The exact prefix, with the exact prefix-length 0.
This is matching a default route.

ip prefix-list LIST permit ge 21 le 29
This means:
Check the first 8 bits of the prefix
The subnet mask must be greater than or equal to 21, and less than or
equal to 29.

When using the GE and LE values, you must satisfy the condition:
Len < GE <= LE

Therefore “ip prefix-list LIST permit ge 8! is not a valid list.

The way prefix lists work are you can specify a network and mask or a
network and a range of masks. Specifying a network and mask is fairly
ip prefix-list mylist seq 10 permit
This will allow (match) the exact network to pass the list.
However prefix lists can also specify a network with a range of masks. For
ip prefix-list mylist seq 10 permit ge 24 le 26
This will take the entire class B network ( and
pass only subnets with a /24, /25 or /26 mask (ge 24 le 26). So the exact
network would actually fail the list because it does not have
a mask of /24, /25 or /26.
By default if you only specify "ge" then any subnet with a mask greater than
or equal to the ge value will pass. That is, ge all the way up to /32. For
ip prefix-list mylist seq 10 permit ge 28
This list specifies any subnet within the range that has a
mask of /28 or greater ( to Again, the
exact subnet would fail because it does not have a mask of /28
or greater.
By default if you only specify "le" then any subnet with a mask less than or
equal to the le value but greater than or equal to the mask specified will
pass. That is, le all the way down to the mask listed. For example:
ip prefix-list mylist seq 10 permit le 23
This list specifies any subnet within the range that has a
mask between /16 and /23, inclusive ( to In this
case the exact subnet would pass because it has a mask in the
range /16 to /23.
The "permit any any" in a prefix list is:
ip prefix-list mylist seq 200 permit le 32
I recommend getting quite familiar with them because they are very powerful
and actually not too bad to use once you get used to them!
Hope this helps


Anonymous said...

dear Jorge

it seems you have commented on my blog EGO OUT; it is in gmail but not on the Blog.
Please write me to
if you wish to discuss and please

warm greetings!

Anonymous said...

I'm pretty pleased to discover this great site.
I wanted to thank you for ones time for this particularly wonderful read!!

I definitely loved every little bit of it and I
have you book-marked to look at new stuff in your site.

my web blog; 8 Ball Pool Cheats

Anonymous said...

Hey there I am so happy I found your webpage, I really found you by mistake, while I was looking on Yahoo for something else, Regardless
I am here now and would just like to say thank you for a tremendous post
and a all round thrilling blog (I also love the theme/design), I don’t
have time to read through it all at the minute but I
have saved it and also added your RSS feeds, so when I have time I will be back to read more,
Please do keep up the fantastic jo.

My web page :: finding a local roofing company

Anonymous said...

Training and motivating your team members encourages happier
customers and more sales. The leverage of the
Internet is the greatest power a person can use now.
Article Source: the information and details
you need to build and thriving and successful
MLM business today.

Look at my web page - lyoness canada Scam

Anonymous said...

It is appropriate time to make some plans for the future and
it's time to be happy. I've read this put up and if I may
I want to suggest you some fascinating things or tips.
Maybe you could write subsequent articles
regarding this article. I want to read more
issues approximately it!

Also visit my weblog; ครีมหน้าใส

Anonymous said...

I'm not sure where you are getting your information, but good topic.
I needs to spend some time learning more or understanding more.
Thanks for great info I was looking for this info for my

Look at my web site - p3636

Anonymous said...

Very nice post. I just stumbled upon your blog and wanted to say that I have really enjoyed browsing your blog posts.

After all I will be subscribing to your feed and I hope you write again soon!

Also visit my web page - how to make a hen coop ()

Anonymous said...

Hey! Do you use Twitter? I'd likle to follow you if that would be okay.
I'm undoubtedly enjoying your blog and lpok forward to new updates.

Check out my web page ... clash of clans hack ifile

Anonymous said...

When I originally commented I clicked the "Notify me when new comments are added" checkbox and now each time a comment
is added I get several e-mails with the same comment. Is
there any way you can remove people from that service?


Here is my web page :: rapid muscle growth

Anonymous said...

With Search Sub Engines you list you site for any length of time
between 1 and 28 days and during which time your listin is gradually flrced
towards the very top result for your category. You can search foor the suitable vacancies and get in touch with the employers
through the cpntact details which may include email id, postal address, phkne numbers etc.
In fact, it will operate best when you use the free advertising to give something
off value away in orderr to establish a condition of trust
between yourself and a prospective customer.

my page ... advertise your business for free;,

Anonymous said...

This free kit is known as BREW SDK (Software Development Kits).
Construction site permits, licenses and safety protocols must be in place
before the first spade of dirt is removed from the
construction site. A keen internet user will always remain on the look out
of a good quality new software to upgrade his system.

Feel free to surf to my web site ... Online photoshop Retrica

Anonymous said...

New and redistributed ones are never used by the customer and they were just inspected upon being sent back into the store just to make sure that the package is not tampered and they have not been used at all.

This is a large fraction of the cause why
laptops are superb and best gadget for an easy professional existence.

You can get very cheap rates for the second hand laptops.

My page ... laptop second hand ieftin timisoara

Anonymous said...

Greetings. I am wondering if you might be interested in doing a website
link exchange? I notice your blog: and my blog are
centered around the same subject matter. I'd love to switch links or perhaps guest author a post for
you. Here is my personal contact:
Make sure you contact me if you're even slightly interested.

Here is my site ... Clash of Clans Cheats

Anonymous said...

Howdy juѕt wanted to give yyou a quick heads up. The teҳt in your
content seеm to be running off the screеn in Firefox.
I'm not sre if this is a fortmatting issue or solmething to do with weeb browser compatibility
but I fijgured I'd post to let you know. Thee design look great though!
Hoрe you get thе issսe fixed soon. Kudos

Looқ att mmy web blog buildium vs tenant pro;,

Anonymous said...

Great site you have got here.. It's hard to find excellent writing like yours nowadays.
I truly appreciate people like you! Take care!!

Here is my web blog :: grapefruit diet plan

Anonymous said...

Waste water (H2O) is any type of H20 of which the standard has been negatively affected by human activities.
Aerobic wastewater treatment plants basically produce waste sludge.
Thus not only is the surface area maximized, but so is the amount of time each bubble spends in the water,
allowing more time to transfer oxygen to the water.

Take a look at my blog ()

Anonymous said...

I do not even understand how I finished up right here, but I assumed this post was once good.

I do not know who you are however definitely you are going to a well-known blogger in the event you are not already.

my homepage; nail hardening treatments

Anonymous said...

These high fat choices lead to weight gain and healthy ailments like
high blood pressure and high cholesterol. Another factor that we have to think about when we choose our cooker
hoods is the brand. A one metre diameter parabolic which has been engineered to a high spec will pump
out more than enough heat to boil water in a few minutes.

It's not very difficult to understand exactly why large
electric ovens are a fantastic purchase.

Here is my web-site where to get ninja cooking

Anonymous said...

What's up, all the time i used to check webpage posts here in the early hours in the morning,
since i enjoy to learn more and more.

Here is my blog post - Spokane Massge

Anonymous said...

Everʏone’lmost all usuallƴ ɦave tօ go back along wіth participate іn f mission a second or pοssibly
tɦird time fοr you to try tо full tҺe pursuit’s pгoblem.
I ϲan virtually like all night at a stretch օn a single video game үet still ԁo not evеr ǥet ʏourself а sport dߋne nicely.
An ɑrea, you can find a fashionable in wɦich femnale partner ɡive other forms ffor
reward tο their bride rathr tҺan wedding ringgs but male found jսst engagement
wedding rings.

Stоp by myy blog post; spider solitaire game download

Anonymous said...

Then traveling and making money off timeshare is the way too go.
Think Oprah Winfrey or Billl Gates here folks and quit blaming the rich for ypur misfortune.
That should give you some free moey earened from the internet right.

Anonymous said...

Wonderful website. Plenty of helpful info here.
I'm sending it to a few pals ans additionally sharing in delicious.
And of course, thank you in your effort!

Visit my web blog - clash of clans cheats (

Anonymous said...

It's actually very complicated in this full of activity life to listen news on Television, thus I simply use the web
for that purpose, and obtain the most recent information.

Here is my site home inspector long island

Jorge Arredondo Dorantes said...

hey guys thank you very much for all your comments. I just try to help the networking community worldwide hope it helps.

I'll keep posting networking stuff about CCIEv5 routing and switching exam

Anonymous said...

I enjoy reading an article that can make men and women think.
Also, thank you for allowing me to comment!

Feel free to visit my blog buy wartrol australia

Anonymous said...

I'm curious to find out what blog platform you happen to be utilizing?
I'm having some small security problems with my latest site and I would like to find something more secure.
Do you have any solutions?

Here is my web page: steam iron reviews

Anonymous said...

I know this web pahe giveѕ qualitу depending articles or reviews and other
material, is tҺere any othe website whіxh offеrs hese stսff in quality?

Feell ffree to surf to my ѕite - divorce court records

Anonymous said...

Attractive section of content. I just stumbled upon your website and in accession capital to claim that
I acquire in fact enjoyed account your weblog posts.
Any way I'll be subscribing to your feeds and even I achievement you get right
of entry to persistently fast.

Feel free to visit my weblog best baby skin care products

Unknown said...

pou hack money for free...hack pou and win potions

Cisco Systems