Dear Eli Your tutorials are the most clear and exciting I have ever seen. You make me understand everything you demonstrate, explain and present. You have skills and great knowledge of real practicals of computer world. I'm impressed because I have been to other countries to study what I should have acquired sitting in front of my PC at home. Thanks for helping me understand better.
Lol i feel bad for people trying to understand the accents especially thick native ones. I'm soo so thankful I can understand it because Indians do have an excellent and prolific grasp on IT, in general. So yeah I definitely feel for you guys! Ahahah
I appreciate everything you do so much Eli, thank you. I try to share your videos as much as possible. Thank you so much for everything you've taught me.
To hear the lesson on both ears, download the video and open it with the latest version of VLC (older version may not suppport this). Then: - Right click on the screen - Audio - Stereo Modality - Left So you will hear the sound from the left side on both hear when using headphones!. Thank you Eli for your videos!!!
First of all, I must thank you. With this video series, you opened my mind to new possibilities that I was unable to consider before, making my complex nodes of thought to loosen their tight , making things easily understandable (to the point I wasn't able to concentrate on your talking cause I was thinking how to apply the beautiful things I just have understood). You're easily understandable thanks to the high PNL skill applied in your speech. While getting things really easier to understand you can even guide these poor sheeps to the village's marketplace! Thanks Computer guy, you have my trust!
A little tip for all new DOS users; typing "help" (not including the ""), alone or after a command, will give you options for that command. If typed alone, it gives a comprehensive list of commands. So for example; ping /help will give you a list of arguments for the ping command. Another essential DOS cmd set to know for networking would have to be to understand and know how to reset winsock and understand netsh.
Ely. you are a natural teacher. It is great to listen and learn from you. The problem I have is I cannot organize your lessons in the right order, so I listen to different subjects as I find them...but, again - every lesson is always very well organized, professional etc. By the way, there is a problem with the fact that technology changes quickly, for example, in comm cables there is cat 7..(the red cable), but I understand that it is not possible for you to update, and it is really not that critical. So thanks a million. Arik
As an IT professional, these videos are great for getting perspective, handing off to the new guys to get them on a jump start, etc. However, as IT professionals, it usually requires headphone use at work and your audio is only left channel which is incredibly irritating.
I'm almost certain that TTL in a ping is not a time-counter but a hop-counter. it means that a packet can pass so much hops until it dies, where each node it passes means one less TTL record. by default an ICMP gets on the road with 255 hops which includes both directions (i.e. 128 is max TTL you``ll see when there is only one router to pass) I may be wrong but I`m pretty sure I`m not
+willow klan Actually TTL is a time counter. The minimum amount that can be reduced is one second. Nowadays routers process packets in less than a second, that's why the TTL is reduced by one at every hop. Theoretically, if you somehow can stop the packet at your router for 3 seconds, then the TTL will be reduced by 3. I guess, nowadays it is not a mistake to consider TTL as a hop counter, but one should be aware of the underlying nature, just in case.
+Sergey Khegay reason for TTL is to kill packets that else would continue to go around forever. Each relay device (routers) shall reduce TTL by one each time they handle a packet. Sender sets initial value as wish. This is how tracert works. First paket has TTL=1, first device shall decrease it to 0 so you get an ICMP error message from this device and log it. Next comes TTL=2 so you get the error message from the SECOND device, counting outwards like an onion, and so on. tracert with maximum 30 hops means that it shall try up to 30 steps or TTL value before it stops it.
Useful arguments to ping are *-t* to ping continuously until stopped, and *-w* to set the timeout. You can use ping in batch files to insert a pause of any length by pinging a non-existant network and waiting for a timeout w. The TTL is hardly useful in ping because the default of 64 hops and timeout of 4s are plenty for any network. Australia is 20 hops and 350 ms away from europe. Furthest places like China might be 30-35 hops. If you placed 65 routers inbetween you and the destination, or a routing loop which somehow resolves, a response with TTL of 64 set by the remote machine would never make it back anyway. Traceroute works by sending multiple pings or udp packets with different, increasing TTL values to give a complete picture of the route _towards_ the destination. Each router our packet passes through decrements its TTL value, and when that value reaches 0, the router sends back an ICMP response. It is sometimes useful to use ping and traceroute _on a router_ to see the route taken from their perspective. A response packet _from_ the destination might be routed over a different path. If a host cannot be pinged because its set to not send out ICMP in the firewall, traceroute can still be useful to determine the latency of the last hop that did respond. If the remote computer is down and doesn't respond to ARP, that last router will also usually send back an ICMP "host unreachable". The Windows command interpreter isn't "DOS". I would also never turn ping off. It's quite handy to troubleshoot speed or packet loss issues. Good routers can be set to limit the rate of echo messages sent to minimize flood.
You have listed the most important steps to do manual network mapping. But, I believe, consultants these days need an automated network discovery tool to map it, and then export it to Visio, PNG or any other formats they may like. There are quite a few network topology mapping tools out there!
You are awesome.. For protecting our privacy that our goverment violates everyday.. Everybody needs to protect themselves. Please teach us about cyber security.
Correct me if I'm wrong but the Time To Live (TTL) has nothing to do with time and everything to do with the number of hops the ping can survive for before being returned to sender. A hop is effectively a router in this scenerio. Traceroute works by sending a pings with a TTL of 1, then 2, then 3 and so on. Thats how it knows the route the packet takes ;) I've not explained as well as perhaps it could have been, but you can read more at www.grc.com/sn/sn-313.txt, about two thrids down, search for Traceroute.
Every protocol sent through tcp/ip network has a time to live = TTL, and that TTL number decreases after every device the protocol goes through and when it hits zero the protocol is destroyed
Awesome video. Thank you so much for uploading this. I was finally able to settle an argument with my cousin regarding discovering MAC addresses on a network.
You aren't too old. You just have to keep learning. Right now everybody's getting involved in cloud systems. Learn about that. Actually, learn about everything about computer programming you can. Keep up to date with Java and everything misdirectionx talks about.You have to update yourself, sense technology is always chaging. Basicvally, keep watching youtube videos on this stuff.
@17:20 Time to live (TTL) doesn't indicate latency or delays in the system. It's how many hops the packet will take before giving up. The latency is indicated by the "time" field. Additionally, increasing the TTL will not increase the chances of a packet surviving a single flaky hop. Its just there to prevent networks from having immortal packets hopping around in circles.
i love the key point links in the vid description for reference you are the best. I'm currently taking electrical engineering in school and am learning networking/ programming on the side this is so helpful due to my time constraints thank you much man
Just fyi, the TTL isn't a stat in milliseconds.. rather, it's "router hops." It's a mechanism IP uses to ensure packets don't run around endlessly. When a router gets a packet, it lowers the TTL field in the header by 1. If doing so puts it to 0, it will send ICMP time exceeded back to the source. That's how trace route works. 3 packets are send with TTL of 1, and the first router sends back an error, which the tracert program shows as the first hop. Then it sends 3 packets with TTL of 2, etc
I'd like to say that for some companies and savvy computer users you can block ping request or ICMP requests to your router to better hide yourself. This can also give you an unreachable error as well.
Introduction (00:00) How Network Mapping Works (03:12) DOS Tools (11:44) Network Mapping Software (34:54) Security Considerations (44:14) Final Thoughts (48:21) Class Notes
Hey Eli. Question for u. I have my art router/gateway and then I have two routers connected directly to it making two separate private network running off that primary router gateway. If I connect a NAS DIRECTLY TO THAT ATT ROUTER/gateway, will all devices connected to the other two networks be able to access and share data file transfer etc? And if not what is missing to get the NAS accessibly by all networks connected to the att gateway?
I was able to land two jobs at the same time. I am going to go in depth in Database and User Interface theory in grad school and move away from help desk and tech support. Thanks
Echo Request in a nut-shell: Q: Hey other computer, are you there? A1: "Yes, I'm here and I'm doing great." A2: "I'm here, but I'm fu*ked up bad, fam." A3: [ no response ]
There are some issues with ipconfig release where some computers do not seem to either release or request a new IP address properly. In windows 10, there is a function called "Reset network" which reinstalls the network card drivers among other things but it does solve the issue.
Enjoyed The Class! I Love Your Classes! My Brother learned from you and he told me to come here cause he said you are a god at everything computer related! Lol But hope to hear from you back!
Cool tutorial, love it I have a feeling ill spend a lot of time on your channel. Little advice though if you haven't already figured it out. You should record record your sound in stereo sorry I was watching with headphones, and it was kind of annoying hearing only my left speaker outputting sound.
Yup. However, if it is a public network, windows computers have a setting called "public" which makes the firewall rules much more strict, you might not be able to do a port scan or the such, but you can tell that they are there, because they will still respond to ping requests.
Generally the IP would be the gateway, however if you run a tracert, you will see every router that information will run through. More the likely the first router would be the colleges something like 192.168.1.1. FYI, that IP will be a LAN ip not a public one.
Is there a way to map a URL as a drive?? I have a WD My Cloud (NAS drive) and would like it to act like a drive (like it does when I'm on my home network) outside of my network. I can access this drive by going to mycloud.com, but when I try to map that address as a drive letter, it says it can't connect. How can I map this drive to work as a drive letter when I'm outside of my network? One example it with OneNote it syncs to this drive mapped as drive letter Y, I'd like to be able to open and access the notebooks like it does when I'm on my network over the internet.
hello Eli, I did a ping command to your everymanit.com from Toronto where I'm right now and there were 30 hops and one of the router responded with "request timed out". is that mean they have turned off ICMP inbound requests?
Hey, love your videos and patience. could you please share the knowledge on How storage arrays like Dell EMC vmax used , mapping of LUNS ,eNAS , DWDM ,This provisioning etc..
Better than a college education! I just graduated from UC Santa Barbara (a school within the top two percent of all schools in the nation) I was just thinking how that degree is worthless and how this information will further my subsistence far beyond what any university degree would. Please keep up the vids....They are extremely helpful to me as a newbie in the IT business. Also, I'm just curious, do you still own a computer repair shop? thanks
when i type in tracert www.google.com or any other domain i get abut 4 5 request timed out messages and then it connects to the domain, why am i getting these time outs?
Actually its -w for setting the TIMEOUT. Time to live is how many hops, before the packet gets dropped. Traceroute actually works by pinging the host, with first a TTL of 1, 2 ,3 ,4 etc.
I've had a major issue getting the product keys retrieved from Office 2013. For software audits do you have any suggestions for software that works. I have tried lots of different key finders and none work for Office 2013.
TTL=64 doesn't mean that every router-modem etc that reicives the packet will decease this number,until gets 0,and then the router that makes it 0,will destroy the packet?
Love your vids Eli...but if you happen to cover Audio editing/authoring in an upcoming segment, can you use this vid for the demo, and re-upload so my speakers aren't maxed out, where getting an email scares the shit outta me?
You would have to get the friends public IP address. Each modem will have the public IP, and the router/networking device, will set up a subnet, giving each device a local IP, normally something like 192.168.1.2. To get that IP, while in a session, type netstat -a. This might just give you the facebook IP though cuz communication goes through their server. your best bet would a direct session. In order to sniff his LAN IP, you would have to become apart of the network he is on.
Actually if windows is setup to pull an address from a DHCP server and it can't pull and address it will create an apipa address of 169.254.X.X. Not necessarily a 0.0.0.0 address.
old schooler in me remembers ping floods used to work, larger packets [amplification effect] could be accomplished with finger requests. echo's being limited in response/request size en.wikipedia[dot]org/wiki/Finger_protocol
Great videos, I'm hooked. But I have another question. If I disable ping request to my router will that prevent DoS attacks using IP stressing on my Xbox live games?
Forgive me, but I don't feel like SMB Shares were sufficiently explained in this video. Could you elaborate a bit more on how they related to Port-scanning and SNMP? Thanks
Hey Eli, your networking videos are so amazing and I'm taking advantage of it to add up my skills in networking. By the way, do have a website for your organization? if so, pls send me the link.
there are many dns servers how one dns server is connected to other if one of the the dns server is down when there is problem of same domain registered how this thing work is there only one major dns to control minor dns server
