1 00:00:02,330 --> 00:00:08,653 [music] 2 00:00:08,653 --> 00:00:14,593 All right, next we're going to take a look at IPv6 DHCP 3 00:00:14,593 --> 00:00:16,027 prefix delegation. 4 00:00:16,937 --> 00:00:22,461 Now the basic idea behind this one, this one gets a little bit trickier 5 00:00:22,462 --> 00:00:25,455 as far as the set up and the configuration goes. 6 00:00:26,388 --> 00:00:32,003 So let's take a look at our topology and we can take a look at what 7 00:00:32,004 --> 00:00:34,580 we're going to set up and what we're going to do here. 8 00:00:34,581 --> 00:00:38,480 So I'm going to spend a second on the topology now on this one. 9 00:00:38,481 --> 00:00:41,977 So for those of you who been follow along with the lessons here so 10 00:00:41,977 --> 00:00:47,988 far we've been using VLAN 36 between Router 3 and Router 6 11 00:00:47,989 --> 00:00:52,776 where for slack and normal DHCP and so on, 12 00:00:52,777 --> 00:01:00,913 Router three has actually been the DHCP server or the router itself 13 00:01:00,913 --> 00:01:04,892 for slack, and Router 6 has been playing the role of the client. 14 00:01:04,893 --> 00:01:07,844 We're going to sort of stick with that idea, 15 00:01:07,845 --> 00:01:13,462 but the idea with prefix delegation is a service provider or somebody 16 00:01:13,462 --> 00:01:15,347 else, it could be within your own company, 17 00:01:15,348 --> 00:01:19,726 but the idea is, that a service provider actually gives you the prefix 18 00:01:19,727 --> 00:01:23,456 that you're going to use inside of your network. 19 00:01:23,456 --> 00:01:29,659 You then, take that prefix, you break it down into subnets and you 20 00:01:29,660 --> 00:01:33,150 use that on the interfaces inside of your own network. 21 00:01:33,151 --> 00:01:35,249 That's what we're going to take a look at. 22 00:01:35,250 --> 00:01:39,589 To do this, we're actually going to use Router 4 now, 23 00:01:39,589 --> 00:01:43,637 so we're going to go down across VLAN 344 here and we're going to 24 00:01:43,638 --> 00:01:48,939 use Router 4 as the DHCP server this time. 25 00:01:48,939 --> 00:01:52,843 It's going to send not an address, this is the big difference. 26 00:01:52,844 --> 00:01:56,313 It's not going to be sending me an address to Router 3. 27 00:01:56,314 --> 00:02:02,627 No, no, Router 3 is instead going to be getting the address from 28 00:02:02,628 --> 00:02:08,951 DHCP, and then using that, and reallocating address space to the devices 29 00:02:08,951 --> 00:02:14,555 inside. And for the inside, I'm actually going to use the link up 30 00:02:14,555 --> 00:02:21,410 towards Switch 3, so VLAN 39, and VLAN 36 as examples on how this 31 00:02:21,411 --> 00:02:28,253 works. Our steps, sort of like before, are going to be to configure 32 00:02:28,254 --> 00:02:34,793 the Router DHCPv6 scope, but this is going to be for prefix delegation 33 00:02:34,794 --> 00:02:38,063 this time. So, that's going to be Router 4. 34 00:02:38,064 --> 00:02:40,418 Configure that on the interface. 35 00:02:40,418 --> 00:02:44,465 Then we're going to set up Router 3 as our client. 36 00:02:44,466 --> 00:02:50,979 Again, we can still control the host portion with link-local, 37 00:02:50,980 --> 00:02:52,727 but we don't even need to do that. 38 00:02:52,728 --> 00:02:56,083 We're going to see how to do the interior addressing. 39 00:02:56,083 --> 00:03:01,306 Configuring the DHCPv6 client, that's actually the the big part of 40 00:03:01,307 --> 00:03:05,939 this section, so let's just jump in to the command line here. 41 00:03:05,939 --> 00:03:14,559 What we're going to need to do is go to router 4 and like I said, 42 00:03:14,560 --> 00:03:16,733 this is going to be our server now. 43 00:03:16,734 --> 00:03:25,858 So we're going to say, ipv6 dhcp pool, and we've been using 6pool 44 00:03:25,859 --> 00:03:28,648 this whole time so we can stick with that it's not a big deal you 45 00:03:28,648 --> 00:03:30,030 can call it whatever you want. 46 00:03:30,031 --> 00:03:31,856 Here's the big difference. 47 00:03:32,592 --> 00:03:37,726 Now instead of saying address prefix, instead we say, 48 00:03:37,726 --> 00:03:39,403 prefix delegation. 49 00:03:39,404 --> 00:03:43,668 Now at this point I could a prefix right here, 50 00:03:43,669 --> 00:03:47,437 but that would really just be assigning one prefix. 51 00:03:47,438 --> 00:03:51,087 The more common thing to do and of course you could always use AAA 52 00:03:51,087 --> 00:03:52,527 here as you can see. 53 00:03:52,528 --> 00:03:55,920 But the example I'm going to show the more common way that I've seen 54 00:03:55,920 --> 00:04:00,563 done is to actually call to it from a local pool. 55 00:04:00,563 --> 00:04:02,931 And then of course, you have to give it a name, 56 00:04:02,932 --> 00:04:12,288 which would be something like Local 6Pool - something like that. 57 00:04:12,289 --> 00:04:20,496 If you want, as always, lifetime 600 preferred 300 - whatever you 58 00:04:20,497 --> 00:04:24,745 want to do. Also, of course, your DNS server. 59 00:04:28,747 --> 00:04:31,004 In case anybody's wondering what I'm putting in there, 60 00:04:31,004 --> 00:04:34,692 I'm just using Router 1's loopback from our topology. 61 00:04:34,693 --> 00:04:37,286 It doesn't matter, it's not a DNS server anyway. 62 00:04:37,287 --> 00:04:43,043 Then, domain name ine.com. 63 00:04:43,043 --> 00:04:46,019 So, all the typical things you would want to do. 64 00:04:46,020 --> 00:04:51,754 Now, there's two more pieces, the tricky part and the easy part. 65 00:04:51,754 --> 00:05:00,367 Let me exit out of this, and we're going to say IPv6 local pool and 66 00:05:00,368 --> 00:05:05,611 we'll call it local 6Pool. 67 00:05:05,612 --> 00:05:07,750 This has to match of course, what we did above. 68 00:05:08,630 --> 00:05:13,222 This is possibly where people start getting a little bit confused 69 00:05:13,223 --> 00:05:21,361 by this. We're going to say 2001: and remember so far we're at 16, 70 00:05:22,297 --> 00:05:37,699 that's 16 bits, :DB8 32 100:: Now, technically that's 48 bits that 71 00:05:37,700 --> 00:05:39,052 I just defined there. 72 00:05:39,052 --> 00:05:42,294 Remember that the 100-- and technically if you just want to spell 73 00:05:42,295 --> 00:05:46,885 it out, remember that 0 100, that's 0DB8, 74 00:05:46,885 --> 00:05:48,537 doesn't really matter. 75 00:05:48,538 --> 00:05:54,351 But remember this, that's 48 bits that I'm defining right there, 76 00:05:54,352 --> 00:06:01,388 but what I'm going to do is I don't want to have-- remember that in this 77 00:06:01,389 --> 00:06:04,467 case, our Router 4 is sort of pretending to be a service provider 78 00:06:04,468 --> 00:06:09,400 or the core of your network or wherever it is you're using this feature, 79 00:06:09,401 --> 00:06:14,211 the idea is I want to have more than one prefix. 80 00:06:14,211 --> 00:06:20,207 And I want to give the customers a /48 because if I give the customer 81 00:06:20,208 --> 00:06:27,949 a /48 then they can then create a /64 for their internal subnets. 82 00:06:27,950 --> 00:06:33,133 And that gives them 16 Bits of subnetting or 65,000 roughly subnets. 83 00:06:33,816 --> 00:06:40,066 So if I'm going to give the customer a /48 then this pool that I'm 84 00:06:40,066 --> 00:06:42,830 creating should be smaller than that, 85 00:06:42,831 --> 00:06:48,468 or a shorter prefix length. Just as an example, 86 00:06:48,468 --> 00:06:54,333 /40. That means I'm going to look at the first 40 bits of this. 87 00:06:54,333 --> 00:06:58,485 Now the reason I used 40 just in my example here just so you know 88 00:06:58,486 --> 00:07:03,587 is I want to make sure that we're actually going to end up on 100 89 00:07:03,588 --> 00:07:08,600 here. So I want to make sure that the 1 is the first one handed 90 00:07:08,600 --> 00:07:15,748 out. If I say /40 it means that these two zeros are not part 91 00:07:15,748 --> 00:07:17,899 of what I'm defining. 92 00:07:17,899 --> 00:07:24,215 So I'm saying that the first 40 bits of this are the pool and that 93 00:07:24,216 --> 00:07:26,430 would be everything up to the 1. 94 00:07:26,430 --> 00:07:33,370 So I'm saying that the pool is all of that and that's what I'm going 95 00:07:33,371 --> 00:07:34,526 to hand out from. 96 00:07:34,527 --> 00:07:40,133 So everything I hand out will be 2001:DB8:1. 97 00:07:40,133 --> 00:07:46,397 Then the question is how long of a prefix do I actually hand out. 98 00:07:46,398 --> 00:07:51,293 As I told you I want to give the customers a /48. 99 00:07:51,294 --> 00:07:56,590 So the way to read that line right there is I'm creating a pool that's 100 00:07:56,591 --> 00:08:03,193 a /40. But from those /40S I'm going to give out a /48, 101 00:08:03,193 --> 00:08:09,174 which means the first one I give out will be 100. 102 00:08:09,918 --> 00:08:15,909 The second one would be 101, 102, all the way up to 1FF, 103 00:08:15,909 --> 00:08:25,977 so that means that I'm using these two digits or 8 bits for the pool. 104 00:08:25,978 --> 00:08:30,625 So everything from 00 to FF are part of this pool. 105 00:08:30,625 --> 00:08:35,111 And as clients request from that pool he's just going to start handing 106 00:08:35,112 --> 00:08:40,472 out the first addresses, so that creates the pool that I need to 107 00:08:40,472 --> 00:08:45,177 create. So that's what I referred to a minute ago as the trickier 108 00:08:45,178 --> 00:08:54,380 part. The easier part is that we just go to interface FA 0/0.344 109 00:08:54,380 --> 00:08:57,718 that is the subnet going up to Router 3, 110 00:08:57,719 --> 00:09:03,498 if you need to you can refer back to the diagram and we say ipv6 111 00:09:03,498 --> 00:09:13,079 dhcp server 6pool. And while we're at it do debug ipv6 dhcp. 112 00:09:13,080 --> 00:09:17,560 Now we would have missed the DHCP server starting up there since 113 00:09:17,561 --> 00:09:19,768 I didn't turn on the debug until just now. 114 00:09:19,768 --> 00:09:22,251 But we'll still see the request come in. 115 00:09:22,252 --> 00:09:30,498 Okay, so now we go over to Router 3, and on Router 3 we're going to 116 00:09:30,499 --> 00:09:33,343 configure his interfaces. 117 00:09:33,344 --> 00:09:35,592 And this is possibly the trickiest part of the whole thing, 118 00:09:35,593 --> 00:09:41,192 is configuring Router 3 with what to do with this prefix. 119 00:09:41,193 --> 00:09:46,827 So the first is to tell him to get the prefix from Router 4 to begin 120 00:09:46,828 --> 00:09:51,015 with. So interface fa0/0.344, 121 00:09:51,015 --> 00:09:57,394 and here's the fun part, see, we're not going to be saying IPv6 address 122 00:09:57,394 --> 00:10:04,065 DHCP now. No, no what we need-- and you could just do IPv6 enable 123 00:10:04,066 --> 00:10:10,460 here like we talked about previously, but if we said do show IPv6 124 00:10:10,460 --> 00:10:16,419 interface brief I do already have link local address on this interface, 125 00:10:16,419 --> 00:10:18,960 344, so it's going to be okay. 126 00:10:18,961 --> 00:10:20,555 I don't need that. 127 00:10:21,789 --> 00:10:29,362 I'm just going to go right for the IPv6 DHCP client, 128 00:10:29,363 --> 00:10:31,656 and what are we going to be a client for? 129 00:10:31,656 --> 00:10:34,018 Prefixed delegation. 130 00:10:34,019 --> 00:10:39,022 By the way, I could also tell him right there just to get information 131 00:10:39,022 --> 00:10:44,825 from DHCP as well, which is if you don't have the other config flag 132 00:10:44,825 --> 00:10:48,311 like we talked about in that previous lesson this would sort of be 133 00:10:48,312 --> 00:10:51,628 another way to do that as well, but we're here to look at prefixed 134 00:10:51,629 --> 00:10:56,874 delegation. And then this part sometimes blows people away a little 135 00:10:56,875 --> 00:11:01,246 bit, you're then going to give the prefix a name. 136 00:11:01,247 --> 00:11:05,442 And I love that too where it says truncated to 200 characters. 137 00:11:05,442 --> 00:11:08,940 What are you going to call this? 138 00:11:08,941 --> 00:11:12,523 This is the prefix that I got from my service provider that I'm supposed 139 00:11:12,524 --> 00:11:15,129 to use for all of my internal subnets, so this is what I need to 140 00:11:15,130 --> 00:11:19,162 put on here. I don't know why in the world you'd be at 200 characters 141 00:11:19,162 --> 00:11:23,902 for a prefix name but hey, to each their own. 142 00:11:23,903 --> 00:11:31,609 I would call it something like prefix from provider. 143 00:11:31,609 --> 00:11:35,453 You can't imagine having to go any longer than that, 144 00:11:35,453 --> 00:11:40,600 but whatever. One more time, and we did not turn it on on the other 145 00:11:40,601 --> 00:11:43,066 side here. We could, though. 146 00:11:43,066 --> 00:11:48,619 We could go back here and do our pool and say rapid commit. 147 00:11:48,619 --> 00:11:51,181 We could do that. 148 00:11:51,182 --> 00:11:54,851 No harm done. Hop back over to Router 3 just to show you that you 149 00:11:54,852 --> 00:11:56,562 can also say rapid commit on this one. 150 00:12:02,743 --> 00:12:04,376 Should be good. 151 00:12:06,270 --> 00:12:07,848 Was already on, okay. 152 00:12:07,849 --> 00:12:10,260 I was going to try and turn on the debug real quick I couldn't remember 153 00:12:10,261 --> 00:12:12,217 if I had it turned on on Router 3 or not, 154 00:12:12,217 --> 00:12:16,484 I do. So what you can see here is, 155 00:12:16,485 --> 00:12:22,146 he starts up DHCP fine, goes from idle to solicit, 156 00:12:22,147 --> 00:12:25,566 sends the solicit message to all DHCP servers, 157 00:12:25,567 --> 00:12:30,851 he gets the reply from Router 4, adds the server to his list and 158 00:12:30,852 --> 00:12:36,010 then adds the prefix to the prefix from provider name. 159 00:12:36,011 --> 00:12:42,763 If you notice, he grabs DNS and domain name so grabs the options 160 00:12:42,764 --> 00:12:44,206 and then that's it. 161 00:12:44,206 --> 00:12:45,846 He goes to open. 162 00:12:45,847 --> 00:12:49,323 Notice there's no message here about assigning it to an interface 163 00:12:49,323 --> 00:12:51,043 because he's not. 164 00:12:51,043 --> 00:12:56,408 If I said do show IPv6 interface brief we don't have any address 165 00:12:56,409 --> 00:12:57,827 from that pool yet. 166 00:12:57,827 --> 00:12:59,388 We're not using it. 167 00:12:59,389 --> 00:13:04,439 We've gotten it and we've stored it that's all we've done so far. 168 00:13:05,717 --> 00:13:09,936 So the next part is where we actually use it. 169 00:13:09,937 --> 00:13:18,147 So we could say for example interface FA0/0.36 and now the other fun 170 00:13:18,148 --> 00:13:23,956 side of this. IPv6 address and so far we've been typing things like 171 00:13:23,956 --> 00:13:28,241 auto config and DHCP or typing in an address. 172 00:13:28,242 --> 00:13:33,375 But notice you can also just put in a prefix name. 173 00:13:33,375 --> 00:13:36,513 Oh G, I think that's what we want. 174 00:13:36,514 --> 00:13:38,562 Let's put that name in. 175 00:13:40,763 --> 00:13:46,283 Now here's the part where people sort of give you the great big huh. 176 00:13:46,283 --> 00:13:51,217 Yeah, I know. See here is the thing. 177 00:13:51,217 --> 00:13:56,680 You theoretically-- now we know because we set up the server. 178 00:13:56,681 --> 00:13:59,617 We know that we're getting a /48. here people sort of give you the great big. 0:13:45.540000 --> 0:13:48.640000 Huh? Yeah, I know. 0:13:48.640000 --> 0:13:51.540000 See, here's the thing. 0:13:51.540000 --> 0:13:53.560000 You theoretically. 0:13:53.560000 --> 0:13:57.900000 Now we know, because we set up the server, we know that we're getting 0:13:57.900000 --> 0:14:03.560000 a slash 48. But technically you don't really know that. 0:14:03.560000 --> 0:14:06.960000 I mean, what if the service provider was giving you a slash 32? 0:14:06.960000 --> 0:14:10.320000 And you've got a couple, I don't know what would that be, quadrillion 0:14:10.320000 --> 0:14:11.680000 or something, subnets? 0:14:11.680000 --> 0:14:12.820000 I don't even know. 0:14:12.820000 --> 0:14:16.320000 Okay. But the point is this. 0:14:16.320000 --> 0:14:17.500000 It would actually be what? 0:14:17.500000 --> 0:14:21.000000 4.2 billion subnets because you'd have 32 bits of subnetting left. 0:14:21.000000 --> 0:14:23.760000 But the point is, you don't really know. 0:14:23.760000 --> 0:14:25.500000 Did they give you a slash 32? 0:14:25.500000 --> 0:14:27.400000 A 40? A 48? A 48? 0:14:27.400000 --> 0:14:32.860000 What we need to do is we need to finish off the address. 0:14:32.860000 --> 0:14:36.260000 We need to specify the end of the address. 0:14:36.260000 --> 0:14:41.140000 We don't know what the beginning is or how long the beginning is. 0:14:41.140000 --> 0:14:44.840000 And I'm saying all of that just to show you that you're going to start 0:14:44.840000 --> 0:14:46.780000 this with colon colon. 0:14:46.780000 --> 0:14:50.280000 And that's the part I think that sometimes really throws people. 0:14:50.280000 --> 0:14:55.000000 Because we're going to say colon colon and then the subnet, see, that's 0:14:55.000000 --> 0:14:57.160000 our subnetting part now. 0:14:57.160000 --> 0:15:02.900000 So that is going to be the bits between the 48 and the 64 in the network 0:15:02.900000 --> 0:15:07.480000 portion. Now in order to tell it which fields those are, that means that 0:15:07.480000 --> 0:15:13.340000 I have to say colon zero, colon zero, colon zero, colon three. 0:15:13.340000 --> 0:15:19.080000 I have to fill in the whole rest of the host portion. 0:15:19.080000 --> 0:15:24.440000 Just like any other time, you can't use colon colon twice. 0:15:24.440000 --> 0:15:29.620000 So there is no way I could say colon colon 36 colon colon three. 0:15:29.620000 --> 0:15:33.560000 Because they would have no idea where the 36 was supposed to be. 0:15:33.560000 --> 0:15:38.520000 And I have to use the colon colon at the beginning because, well, I mean, 0:15:38.520000 --> 0:15:40.220000 have to use a strong word. 0:15:40.220000 --> 0:15:45.300000 I mean, if you absolutely knew that you were getting a slash 48, you don't 0:15:45.300000 --> 0:15:47.260000 have to put the colon colon. 0:15:47.260000 --> 0:15:48.800000 But you normally would. 0:15:48.800000 --> 0:15:54.100000 That way if you get some various length prefix from the provider, they 0:15:54.100000 --> 0:15:57.040000 send you a slash eight, not going to happen, but I'm just throwing it 0:15:57.040000 --> 0:16:02.900000 out there. You know, a 32, a 40, a 48, whatever they send you, we're filling 0:16:02.900000 --> 0:16:08.220000 in the rest of it and telling it, by the way, once you get that, use it 0:16:08.220000 --> 0:16:10.240000 as a slash 64, please. 0:16:10.240000 --> 0:16:13.980000 So I'm going to put that address on my own interface. 0:16:13.980000 --> 0:16:22.020000 And at that point, he's now going to put an address on his own interface. 0:16:22.020000 --> 0:16:27.880000 So he pulled that from the provider and then he added that part on from 0:16:27.880000 --> 0:16:35.920000 what we put in. I can do the same thing if I go into interface F A 01. 0:16:35.920000 --> 0:16:41.540000 Same address, but that's not subnet 36. 0:16:41.540000 --> 0:16:43.820000 This is the link going up to the switch. 0:16:43.820000 --> 0:16:45.760000 This is VLAN 39. 0:16:45.760000 --> 0:16:51.020000 So what I'm showing you here is you're literally going to be pulling your 0:16:51.020000 --> 0:16:57.620000 prefix, whatever it is, from the provider and then you're tacking on the 0:16:57.620000 --> 0:17:00.340000 subnet and the host portion. 0:17:00.340000 --> 0:17:03.040000 And everything's fine. 0:17:03.040000 --> 0:17:09.040000 Now the advantage to this and what this is for is in case you change providers. 0:17:09.040000 --> 0:17:12.220000 Now since I'm mostly done with the DHCP part of this here, I'm going to 0:17:12.220000 --> 0:17:17.860000 actually turn this off for the debugging so it's not in our way. 0:17:17.860000 --> 0:17:31.520000 Because now if we go further in, if we go into router six, okay, he is 0:17:31.520000 --> 0:17:34.580000 not going to have an address on his 36 interface. 0:17:34.580000 --> 0:17:39.900000 But the cool thing is we can go back to using router advertisement and 0:17:39.900000 --> 0:17:56.660000 Slack now. So again I can say, I, whoops, not in the interface. 0:17:56.660000 --> 0:17:59.380000 Okay, and he'll pull his address. 0:17:59.380000 --> 0:18:02.520000 But we already know we won't pull anything else. 0:18:02.520000 --> 0:18:09.100000 Do show IPV six DHCP interface, gigabit zero zero dot 36. 0:18:09.100000 --> 0:18:10.820000 He's not pulling anything. 0:18:10.820000 --> 0:18:13.080000 In other words, he's not getting the DNS. 0:18:13.080000 --> 0:18:15.440000 He's not getting the domain name. 0:18:15.440000 --> 0:18:17.760000 And maybe you should and maybe you shouldn't be getting that from your 0:18:17.760000 --> 0:18:19.340000 service provider anyway. 0:18:19.340000 --> 0:18:22.360000 That's not really our discussion right now where this should be coming 0:18:22.360000 --> 0:18:25.760000 from. They're trying to show you how the technology works. 0:18:25.760000 --> 0:18:27.820000 So this brings us to our next point. 0:18:27.820000 --> 0:18:29.460000 Okay router three. 0:18:29.460000 --> 0:18:33.880000 Great. So interface F a zero zero dot 36. 0:18:33.880000 --> 0:18:35.000000 You already know this. 0:18:35.000000 --> 0:18:36.440000 We saw it on a previous lesson. 0:18:36.440000 --> 0:18:42.380000 I need to now say IPV six, neighbor discovery, other config flag. 0:18:42.380000 --> 0:18:48.340000 This will tell router six to ask for more information. 0:18:48.340000 --> 0:18:56.440000 Okay. So now he's set to get information, but he's not getting anything. 0:18:56.440000 --> 0:19:00.520000 Let's take a look. 0:19:00.520000 --> 0:19:04.020000 Actually, Puss should lift that on on router three. 0:19:04.020000 --> 0:19:13.080000 Just bounce it real quick. 0:19:13.080000 --> 0:19:21.180000 It would try to ask again later, but I'm not patient. 0:19:21.180000 --> 0:19:24.040000 Okay. So he sends the information request. 0:19:24.040000 --> 0:19:29.600000 Notice sending request, sending request, sending request. 0:19:29.600000 --> 0:19:31.120000 What's router three doing? 0:19:31.120000 --> 0:19:35.940000 Correct. Absolutely nothing. 0:19:35.940000 --> 0:19:39.740000 Because he's getting a DHCP request. 0:19:39.740000 --> 0:19:44.840000 Not good. Okay. Not good. 0:19:44.840000 --> 0:19:48.060000 By the way, he's getting yelled at because don't worry about this. 0:19:48.060000 --> 0:19:49.960000 This is up on VLAN 39. 0:19:49.960000 --> 0:19:55.940000 This is because VLAN 39 says he's a router and is advertising the prefix. 0:19:55.940000 --> 0:20:00.540000 And so are we, but we're advertising different lifetimes and such. 0:20:00.540000 --> 0:20:04.220000 So it's okay. It's just a conflict because switch three is still up there 0:20:04.220000 --> 0:20:06.020000 and we haven't done anything with him. 0:20:06.020000 --> 0:20:09.360000 He's just running default IPV six config. 0:20:09.360000 --> 0:20:14.420000 So this brings us a good place to wrap up with one more topic. 0:20:14.420000 --> 0:20:19.460000 And this can sort of go back to the old DHCP in the previous lesson as 0:20:19.460000 --> 0:20:22.620000 well. But it just sort of fits here really well. 0:20:22.620000 --> 0:20:28.880000 And that is what in IPV four land, you would be familiar with knowing 0:20:28.880000 --> 0:20:32.120000 it as IP helper. 0:20:32.120000 --> 0:20:36.480000 But you know, IP helper was always sort of a, I don't want to say necessarily 0:20:36.480000 --> 0:20:40.020000 a silly name, but it was more inclusive than we needed. 0:20:40.020000 --> 0:20:42.100000 It would forward a whole bunch of different things. 0:20:42.100000 --> 0:20:46.340000 I can never remember six different protocols or so that it would forward. 0:20:46.340000 --> 0:20:47.700000 And we didn't need those. 0:20:47.700000 --> 0:20:52.260000 All we really needed was the DHCP part, but we all put it in there anyway. 0:20:52.260000 --> 0:20:58.320000 With IPV six, they looked at it and they said, you know, we're just going 0:20:58.320000 --> 0:21:00.240000 to get a little more specific now. 0:21:00.240000 --> 0:21:07.480000 So now it's IPV six DHCP relay, which actually makes a lot more sense. 0:21:07.480000 --> 0:21:09.180000 Set the destination. 0:21:09.180000 --> 0:21:14.000000 Well, the destination is FE eight zero colon colon four, which is router 0:21:14.000000 --> 0:21:16.220000 four is link local address. 0:21:16.220000 --> 0:21:20.820000 And by the way, that does not just to show you. 0:21:20.820000 --> 0:21:23.500000 Well, going around a four, I can't really show you because all I have 0:21:23.500000 --> 0:21:25.180000 running there is link local. 0:21:25.180000 --> 0:21:30.460000 But it just to let you know, it does not have to be a link local address. 0:21:30.460000 --> 0:21:34.140000 I mean, maybe this guy doing the relay isn't directly connected to the 0:21:34.140000 --> 0:21:37.540000 DHCP server. So you wouldn't be able to go link local. 0:21:37.540000 --> 0:21:39.540000 You'd have to put in a routed address. 0:21:39.540000 --> 0:21:42.780000 So I could put in, you know, router ones loop back or something. 0:21:42.780000 --> 0:21:44.080000 There'd be nothing wrong here. 0:21:44.080000 --> 0:21:48.320000 We're saying two thousand one DBA colon one hundred colon one hundred 0:21:48.320000 --> 0:21:50.280000 colon one, whatever. 0:21:50.280000 --> 0:21:51.980000 It doesn't matter. 0:21:51.980000 --> 0:21:56.000000 It's just that with no routing protocols running right now or anything 0:21:56.000000 --> 0:21:59.340000 else, all I'm going to be able to do was really. 0:21:59.340000 --> 0:22:01.480000 FE eight zero colon colon four. 0:22:01.480000 --> 0:22:03.680000 And you don't have to do anything fancy with this one because it does 0:22:03.680000 --> 0:22:05.820000 ask for the interface at the end. 0:22:05.820000 --> 0:22:10.380000 This is, of course, going to be the egress interface towards the DHCP 0:22:10.380000 --> 0:22:16.860000 server. So this is going to be F a zero zero. 0:22:16.860000 --> 0:22:21.380000 Dot three forty four. 0:22:21.380000 --> 0:22:25.640000 And at that point, give it a second here. 0:22:25.640000 --> 0:22:29.040000 You can see router six has probably given up. 0:22:29.040000 --> 0:22:31.420000 He's trying periodically. 0:22:31.420000 --> 0:22:33.740000 But you got to wait for him to try again. 0:22:33.740000 --> 0:22:42.480000 And he should get the information. 0:22:42.480000 --> 0:22:50.880000 Not patient. There we go. 0:22:50.880000 --> 0:22:54.820000 And as you can see now, he sent the information request. 0:22:54.820000 --> 0:22:58.800000 It got relayed. So router three got it. 0:22:58.800000 --> 0:23:03.540000 Sending relay forward to that address out that interface. 0:23:03.540000 --> 0:23:06.180000 Gets the answer. 0:23:06.180000 --> 0:23:08.760000 And I don't remember where the debugging on on for we do. 0:23:08.760000 --> 0:23:11.820000 So it received the relay forward from three. 0:23:11.820000 --> 0:23:13.380000 Used the. I don't remember. 0:23:13.380000 --> 0:23:15.400000 Pool from the interface. 0:23:15.400000 --> 0:23:18.140000 Answered just with the options. 0:23:18.140000 --> 0:23:21.140000 OK, sent the answer back. 0:23:21.140000 --> 0:23:23.420000 And of course, that makes it all the way through to router six. 0:23:23.420000 --> 0:23:28.180000 And now. My internal clients. 0:23:28.180000 --> 0:23:32.280000 Have all of their DHCP information. 0:23:32.280000 --> 0:23:36.900000 Now the advantage to all of this is a lot of people look at all this and 0:23:36.900000 --> 0:23:38.560000 go, yep. OK, see how it works. 0:23:38.560000 --> 0:23:46.620000 OK, fine. Why? Well, the idea here is you could and this isn't the easiest 0:23:46.620000 --> 0:23:48.080000 thing to do. Let's see if we can do it. 0:23:48.080000 --> 0:23:52.300000 See how much we have to undo on router four to do this here real quick. 0:23:52.300000 --> 0:24:01.680000 We will have to undo a bit. 0:24:01.680000 --> 0:24:11.000000 But it won't take too long. 0:24:11.000000 --> 0:24:12.940000 So I'll take that pool out. 0:24:12.940000 --> 0:24:15.560000 Take out the local pool. 0:24:15.560000 --> 0:24:23.160000 Put the local pool back in. 0:24:23.160000 --> 0:24:25.960000 By the way, the reason I'm doing this is it doesn't let you change it 0:24:25.960000 --> 0:24:28.600000 and stuff while it's already in use. 0:24:28.600000 --> 0:24:32.540000 And just for fun, just to make it really easy to see this time, we'll 0:24:32.540000 --> 0:24:39.760000 do like 99. DB eight, ninety nine, 40. 0:24:39.760000 --> 0:24:49.320000 48. And then. We can basically put all of this back in. 0:24:49.320000 --> 0:24:56.680000 There we go. And if we go back to router three. 0:24:56.680000 --> 0:25:01.760000 If we scroll back up to the last time I looked at show IPV six interface 0:25:01.760000 --> 0:25:04.160000 brief, notice that we used to be on 100. 0:25:04.160000 --> 0:25:08.540000 And we had our subnets of 36 and 39. 0:25:08.540000 --> 0:25:18.280000 If we look at it now, notice now we're on 99. 0:25:18.280000 --> 0:25:30.100000 So we just flipped his prefix but still the same subnetting internal for 0:25:30.100000 --> 0:25:37.120000 the customer. So the idea is customer changes service providers. 0:25:37.120000 --> 0:25:44.080000 They get a new prefix from the provider and their entire inside network 0:25:44.080000 --> 0:25:47.860000 completely rein numerates itself. 0:25:47.860000 --> 0:25:52.460000 And we're all still running with all of our same internal subnetting. 0:25:52.460000 --> 0:25:57.540000 But on a whole different IPV six global prefix from a whole different 0:25:57.540000 --> 0:26:02.060000 provider. Now, like I said, that's that's the idea. 0:26:02.060000 --> 0:26:03.860000 That's the theory. 0:26:03.860000 --> 0:26:08.980000 I sit around sometimes and go and who's going to use this? 0:26:08.980000 --> 0:26:17.760000 Who literally has every device on their inside network 100% DHCP. 0:26:17.760000 --> 0:26:20.960000 And or slack like we're doing here. 0:26:20.960000 --> 0:26:25.360000 Either way, the point is you have no static addresses on anything. 0:26:25.360000 --> 0:26:27.920000 Nothing you would have to go manually change. 0:26:27.920000 --> 0:26:31.140000 Now, again, you could make the argument that this will handle the bulk 0:26:31.140000 --> 0:26:35.400000 of your network during a renumbering to another provider. 0:26:35.400000 --> 0:26:38.720000 And yes, okay, maybe I have to go change my printers and my servers and 0:26:38.720000 --> 0:26:40.040000 stuff like that. 0:26:40.040000 --> 0:26:43.100000 But I get most of it. 0:26:43.100000 --> 0:26:45.700000 So that's the idea. 0:26:45.700000 --> 0:26:49.360000 How widespread and how used it's going to be. 0:26:49.360000 --> 0:26:52.900000 I don't know. I don't personally know of any customers using it. 0:26:52.900000 --> 0:26:56.020000 But it's there. That's how it works. 0:26:56.020000 --> 0:27:00.120000 And the good news is, you know, it's really not that difficult to do. 0:27:00.120000 --> 0:27:03.180000 Okay? And we already know how to do the host portion.