Examples of traceroute usage.

now that we know how traceroute works by using the time to live field let's look at some examples in place for our usage choice table that's actually I think pretty cool you can probably use this to impress your friends maybe you need a life partner whatever so but let's look at some examples of using tracer so I'm going to run trace route for my Mac right here which is in my office it's connected to a wireless router and let's start with a really simple example so testify dot CSV uh Buffalo 92 u that's my main work machine is located right across the hall so I would expect that there's a very short path between this machine and testify but let's see how packets would be routed between those two hosts and indeed my intuition was correct it only takes two hops to get to testify so how does this work the first stop is to a wireless router that's sitting right over there that's how this laptop is connected to the Internet then I can immediately get to testify because this is on the local network that is the all these computers are essentially connected to the same local network so this is good this shows you examples on trace route output trade shows me the IP addresses this is the IP address of my work machine one trade at 205 dot 39.4 this is a private IP address that's used by this end of the connection that I have to the router it also shows me the host names here that it was able to look up so I was able to translate this IP address into this particular post name that could be kind of interesting because the host names sometimes tell you a little bit about those particular IP addresses maybe what what I ISP they're a part of or what part of the internet they're in or whatever okay so let's try a little bit more interesting example I'm gonna launch a trace route to New York Times com ok so here's what's happening you can see that I very quickly am down to 18 hops which is kind of interesting now what's happening remember some parts of the internet block the messages the trace route needs to operate and actually if I continue to let this run what I would probably see is that this just is going to go on and on and on because I've reached some part of the network or a trace route traffic is not allowed and so any messages that routers are trying to send back from birds are down the chain are being blocked by that part of the network but we can already see some really interesting stuff so let's go through this this is the same router that was my first stop on the way to testify across the hall but then things start to get start to get different so this now these IP addresses one 28.2 a five these are University at Buffalo IP addresses so here's one hop in the University of Buffalo here's another about the University of Buffalo in another cop another hop another hop in the University of Buffalo and now here's the first IP address right here 38.1 - - it's not part of the University at Buffalo Class B Network it doesn't have the prefix one - a - a - a five so this is new and this actually is one of the two internet service providers that the University of Buffalo peers with that's how we get data from our network out into the corner net and this is is be called cogent you can see that the name of this machine sort of identifies it as part of being part of the coach of network these names are also sort of interesting they might you might be able to look at these and at least be able to guess where some of these routers on campus are located but this is a core campus router that might packet goes through right before it exits canvas one - 8205 nine dot 105 and that router has chosen to route this packet that's trying to get to New York Times comm through one of the two ISPs that uses this is cogent okay so so remember that okay and then and then you can see a bunch of other addresses within codes it's Network eventually we get to something that says New York there's a Newark address here and then we could look at the rest of these but let's launch a different query let's see a different path okay so let's try doing the same thing but we're going to do it to espn.com okay so up until this point we're seeing some well actually we don't see some similar things let's so might not terminate either because again we've hit some part of the network where they're blocking the ICMP traffic the traceroute requires to operate but here's what's interesting so some of these hops are the same I think this OP this up this up this up this up remember we get to this core router on campus 1 282 Oh 5.9 at 105 what's interesting is that that router made a different decision this time about which of you of you DS to ISPs to send this packet up so this time I went to 4 dot 59 and this domain name identifies that router is being run by level 3 so you can use trace route in this case to notice that you be actually appears with at least 2 Internet service providers one of them is level 3 the other one is cogent and depending on which site I'm using Ubese internal router is saying it's actually faster if I want to go to espn.com to route the packet out across level threes autonomous system than it is coaches if I want to go to the New York Times comm it's faster to use coach so this is an example of using trace route it's a really cool tool poke around but then it's a lot of fun there are some tools online that you can use to try to create maps of where your tracer on traffic is going those aren't always that useful because we don't know where all of these routers are on the map but obviously the packets that I'm sending between here and some website are actually traversing a path and physical space and it can be cool if you can find one that works to see sort of exactly where those tops are or at least exactly where we think they're so have fun using trace route use it to impress your friends

Channel: internet-class

Views: 21,557

Rating: 4.9864407 out of 5

Keywords: internet, internet-class.org

Id: AGUrTwIX7b8

Length: 6min 12sec (372 seconds)

Published: Thu Sep 08 2016