Computer Networking Tutorial - 40 - iptables Firewall Rules

[@SourceCodeDeleted]

Best video I've actually seen on this. For those that are going to use this you can try. For all others wanting to have an Idea on syntax -N is to create new policy -I is insert into the policy chain(putting at top) -J is to jump to policy chain -L list policy (-n with out name resolution , -v verbose) -A append to end of policy -s source ip/host -d destination ip/host --dport destination port --sport sourceport --dports 0:65535 multiple ports --src-range/--dst-range 192.168.1.100-192.168.1.200 ip ranges

[@Israel777888]

Gracias por la lista! Sabes si estos comandos de iptables funcionan en cualquier distro de Linux, como Ubuntu?

[@CocaColaCan33]

what does -j do?

[@SourceCodeDeleted]

@@CocaColaCan33 chances are -j is for jump to policy chain.

[@Pzdrs]

tf this is literally more useful than a 45min class

[@techsupport5637]

Yes

[@N0Xa880iUL]

Most classes usually cater to the lowest common denominator. Most peeps from the class don't understand nor grasp this quickly. That's why.

[@J2897Tutorials]

Sorry to hear about your girlfriend.

[@J2897Tutorials]

Nice to hear about the swift replacement.

[@BurgerKingNationalist]

me too

[@YourModulesMayVary]

the best analogy for iptables ever! genius :-)

[@CowboyPilot79]

Hate to tell you this but she's in the house with you

[@robpalomo]

The GF part was oddly specific.

[@THATWASDOPE]

I hope he continues working on this serie he's helpful and funny af xD

[@dudemann7947]

Your channel is so damn good man, really easy to learn and understand. I don't have the words to express it anymore. You should have like a million subs, probably the best teacher about computers here on KZbin :]

[@keineahnungnet]

he has 988k subs :P

[@Robin-on6vo]

@@keineahnungnetHe has 2 millions now !

[@eliasforamitti]

I searched the Internet a lot for such a tutorial. This is the best online computer networking tutorial I think. Please continue!!! You could tell us something about Protocols eg (in general and some important Protocols in detail)

[@fabianvilela9527]

I always love your backstories with everything lol. Keep it up.

[@thedoctor3018]

This is the coolest tutorial I've ever seen so far O_O . Thank you fam !!!

[@pgaikwad06]

I cant imagine Bucky, the girlfriend example you took to explain the concept got into my head straight. Thanks mate

[@PoeLemic]

Thank you for this tutorial. I'm trying to learn how to setup a mail server. And, it's not so easy, coming from a Windows background. But, I'm trying to get into Linux and learn. So, this simple tutorial about iptables is very helpful for me to build up the basic knowledge. Again, thank you. You are a very good teacher.

[@mariopereztexas]

Thanks Bucky, this is the best iptables tutorial I have had; it was both funny and informational. Good luck with the ladies brother

[@oussamaml4161]

wow , this is exactly what i was looking for , i studied this two weeks ago in college but didn't understand a damn thing , now i do , tnx a lot

[@oussamaml4161]

i'm back again , i need this for another exam thanx again

[@r7yz]

Started from video 1 and now I'm here! Really enjoyed your series Bucky and hope you continue it!

[@golamrabbani6211]

+Ryan Zhou I just watched whole 40 videos within 2 days :D got some problem understanding some terms in somewhere but no problem will be clear in some other tutorials ;)

[@zsumr]

thanks man, i started my studies again and this is helping alot

[@themedleb]

11:06 Wait ... Did you say "I will smell you next time"? lol

[@Danjovisagat]

Dropping a single rule is what I needed and you delivered. Thank you.

[@governingchildren]

IPtables has never been more interesting in my life

[@tridenda2459]

I won't ever forget the analogy. lol Thank you so much, everything is clear right now.

[@aminjamous2673]

Hey Bucky, I have seen all your vids in one session. Thanks a lot mate. Great job and effort, easy and smooth. Head up and waiting for your next vids. > liked and shared!

[@ealvinoq]

Awesome! Friend, nice, funny tutorial, it highlight from the rest. You should be famous now.

[@PsyArkron]

1:20 Actually there are five chains, not three. But you're looking at the filter table, which only has those three available. Look at the mangle table and you'll see all of them. There are more tables (five) and more chains (also five).

[@weedlax6938]

I never comment on any post , videos or anything but have to say. " You 're a legend" XD

[@junolee8231]

How does Bucky know so much stuff?

[@CodeJackk]

+Juno Lee He's had a lot of years to learn. Before each video he probably researches it from text tutorials to refresh his mind, because I doubt he can remember everything in all his KZbin videos.

[@KarlWakimLeb]

His information is not that good.

[@Dummour]

Man, wtf, these series ended on the best part when multiple networks get into contact.

[@medsabkhi7189]

this was helarioussss, thank you so much man, you've helped me with my network security exam xD

[@garys3673]

Great GF example, really impressive.

[@hayderh.952]

Brilliant tutorial!

[@meghaumesha3849]

Great Tutorial.

[@hawejago]

This tutorial are briliant! please make another one about routing :D

[@naty685]

loved your examples LOL

[@GarjiO]

Crazy heroin addict girlfriend example was the milestone of the video! You are awesome Bucky!

[@edenr1988]

that was defiantly your best video, "now..she and all of her crazy friends now send me an email.." lmfao

[@sashwin92]

Andrei Neagoie's Hackernoon post got me to this Tutorial !!

[@naveennaidu9768]

Thanks for an awesome video Bucky!! Loved it.

[@roberttortaras9952]

Very well done. This is very similar to Cisco ACL's. Thumbs up.

[@premgondode8364]

i wish i could explain the same scenario in an interview cozit is just superb to remember . thanks bucky

[@shamrock6644]

More in this series/playlist please

[@IvanStipic_Stiiv]

Always fun to watch!

[@m.saifulislamtito7869]

Nice explanation in the easy way to others understanding. Thank you.

[@johnreimers4358]

This was so helpful man thank you! Sorry about your lady issues.

[@summertime5909]

Bucky rules the world of computers!!

[@ngoctintran8583]

Your tutorial is so great. It helps me a lot. I'm waiting for your next video.

[@90hijacked]

Why is this the last video in the playlist? Weren't you gonna cover routing/forwarding?

[@bigo025]

Very very very nice explanation

[@djsharpey]

Very concise video. Thanks for posting 👏

[@ipv4subnet628]

Excellent video very helpful!

[@TechFreak51]

Awesome... THANK YOU... To the point an VERY helpful !!!

[@FacePalmProduxtnsFPP]

This specific example only shows blocking IPs within your local network not WAN... JUST to clarify 192.168.x.x is standard for LAN... but the pattern matches... Also for the example with email, this would only apply if you were hosting your own email server and setting filters to the email server itself, typical email has this feature built in to email settings under "filters" "rules" or similar. But the pattern shows network filtering.

[@montazfilmpolska4945]

this is so funny XDXD it's easier to undarstand because of the humor :)

[@Nihillius]

yoo...you are damnnn...nice strategy huh ❤i understand from you more easily

[@enricocialdini6194]

2:11 When I see Forward do I have to set Forward=1 in sysctl file?

[@JV-sl3ks]

Man! thanks bunch for the amazing video!

[@dhwanisondhi8635]

Really good explanation thanks

[@rahulsaha2859]

waiting for more

[@FXSTRIDDA]

me too, still waiting hahaha

[@patrasculucian2403]

maybe in 2018

[@stefanspinu8784]

still waiting...

[@patrasculucian2403]

Maybe in 2019..

[@spinosaurusbot4974]

still waiting... maybe in 2020?

[@RandomShowerThoughts]

Thank you so much for the amazing tutorial buddy

[@hv3300]

Awesome .Just a quick question what does -j signify?

[@RavenValkyrie]

I like this guy, he's funny 🤣

[@mdafzalahmed4675]

Great explained thanks 👍

[@marcojansen6744]

this is really usefull(even in 2021 XD), thanks man!

[@jeremygerbert614]

blocking port 25 will only allow you to drop packets going out haha. SMTP is for sending mail gotta block IMAP or POP3 LMK if im wrong only been into computers for 2.5 years

[@chanakawijerathna8010]

thank you.superb video set

[@ahora1026]

Dude, why did you stopped your networking tutorial here! we want some more of this. at least cover the FORWARD of iptables. you gave the best understanding of iptables and so for networking. please!

[@AmanKumar-vc2hi]

Is this series complete? I want to learn networking, can i start with this series?

[@OliviD22]

Nice tutorial, thanks .

[@barathsingh8112]

Where can I get the previous tutorials and next tutorial.

[@MrVecheater]

Does anyone know what's the point of ufw (in the console, not the graphical interface) when you type almost exactly the same thing in iptables? I recall that it was supposed to be simpler but you type exactly the same rules in both programs

[@govamurali2309]

Bucky, I got one question. Previously in your videos, you mentioned about setting up firewall rules at the linux server level. Here you showed that you are setting up at the PC level. So when you are in a network with a server/pc's how does it work, do you need to set up firewalls seperately at PC level,server level for each and seperate node or just set up the firewall rule at the router level

[@o00BlackCat00o]

first, its not pc/server, more like client/server. it depends on what you want. for example if the client and the server are on the same network, you have to set the firewall rules in the server because they reach each other directly. if the client traffic comes from other network, you can filter it in the router(gateway) and also in the server too. Usually i filter traffic on host level every time, and if I need it (for security reasons) I also filter it in the gateway too.

[@SushilSavaria]

Anytime i'm stuck with something related to networking, i find a video from newboston and that's amazing.!!!!

[@SomebodyOutTh3re]

Thanks a lot for the tutorials , please can you share your knowledge resources ? i mean when did you learn all that ? thanks again :)

[@Nana-zk9sz]

hey what about blocking all listening services except ssh, HTTP and samba

[@dejanduh2645]

Does this apply only for your network?

[@kasie4life123]

You nailed it. I am definitely going to remember how to use iptables because of your crazy girlfriend and her friends.

[@fadlidipo3324]

i think port 25 is smtp for outgoing email and for input why not use the pop3/imap ports?

[@luckbychance3179]

How I will know the X person internet router IP address, from which he/she is trying to send a message? Also while blocking someone, should I use their device private IP address or Router public IP address? I am very new in this , so maybe these questions can be sly

[@numuboniV]

Got some confusion cleared, Thanks & good luck with your new girl friend

[@abubakarrkargbo4849]

Thanks Bucky, after this what next and help me understand the difference between computer networking and CISCO

[@フォグマシン]

could you block all ip adresses except just one, or forward just one and only one address to some specific destination?

[@SB_3.1415]

yes, keep the allow rule on top of the list and then block everything in the second rule.

[@tom4ever83]

How can you do the same with modsecurity?

[@dileepmeena8749]

i want to block my traffic on port 80 and 443. but these command of iptables can't do it. why.. ?? iptables -A OUTPUT -p tcp --source-port 80 -j DROP iptables -A OUTPUT -p tcp --source-port 443 -j DROP

[@ahmedelmenan895]

what does REJECT do in the iptables

[@rowlandrowland3838]

Apparently, these are for rules filtering data sent from IP on the same network (Private IPs 192.168.0.X). How do we permit traffic in and out if the source was a public IP? Would I have to know the public IP of the crazy girlfriend first?

[@SB_3.1415]

yes, you need to know where it's comming from to block it.

[@amadoucoulibaly6439]

good explanation

[@jatingupta9769]

please help! Do this scenario only works if you run a mailserver and all the computers(including his ex and her friends trying to mail bucky) are connected in a same network ?

[@calebpurvis6195]

jatin gupta correct.

[@SB_3.1415]

nice analogy

[@Ather178]

Thank you so much!

[@ragnarw.eliansson5299]

I'm not any great with networking, but is it by any means meaningful to block the gf's IP-address, considering you almost certainly haven't set up your own mail-server at home. You most likely use some commercial like Gmail for instance. I mean you will not get unmasked traffic directly from her, like Messenger/Skype calls and stuff like that, but she can still message you wherever her data doesn't enter your computer directly, but just a datacenter like Google's mail server.

[@denniswilliamsjr5646]

This really helped!

[@yahyeabdi4998]

i really love the way you teach

[@Popoyo023]

cool example bro

[@ComandanteJ]

As far as i know, SMTP is outgoing, so blocking it on a client wouldnt matter in this case, specially incoming, would it?

[@rabindralamsal]

I guess it should have been POP3 or IMAP.

[@farhanahmad2022]

Maybe he has an email server on the local machine...? 😕

[@ogginger]

Thank you!

[@barakkabilio7728]

If I block an ip address in Kali using a virtual machine, does it also block that ip from the host system?

[@abdelilah_talks]

Nah mate, the two systems are completely separable .

[@kevinkkirimii]

hahaha - heroine bro !!! Yoh

[@bradyhuang5606]

Great video, I have a question if your girlfreind use DHCP and send email to you, what you only can do is to block the network IP right?

[@kmandowrulesps3]

Bucky would it be possible if you can make videos on logical programming, like how do you think when solving problems. It would be a pleasure.

[@techsupport5637]

I like your explanation and sorry about your girlfriend

[@achin4140]

i beg you please tell about The Network layer Network layer concepts, design issues, static and dynamic routing algorithms, shortest path routing, flooding, distance vector routing, link state routing, distance vector routing, multicast routing, congestion control algorithm, internetworking, Ipv4

[@Himeth]

that example was too specific tho🤣🤣

[@illoominate]

When I restart the firewall service, my rules disappear. I tried running iptables-save first, but that didn't help. I'll keep digging. One of these days, as God is my witness, I'll get my machine to accept an inbound UDP packet.