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Let’s look at our first task,
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15.1 for DHCP.
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We’re told on Branch 2 Router 3 to set up a DHCP pool
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and to assign IP addresses to all phones in the range of 177.3.11.0/24.
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However, not to allow addresses .1-20 to be handed out in that subnet.
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To ensure the proper default router,
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TFTP server options are chosen
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will download their files via TFTP
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and we’re told that all phones, both Skinny and SIP,
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from the IP address of the loop back 0 interface.
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So, let’s go ahead and bring up our router.
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We wanna be on router3
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and let’s do a show IP interface brief type 2 exclude unassigned.
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So we only get interfaces that have IP addresses.
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We see that our Fa00.11 and .12.
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Actually, let’s take a look at our topology.
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Let me pull that up real briefly.
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Here’s our topology that we’re gonna be using for this deep dive.
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We see that we’ve got the voice rack diagram
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and we’re using the classroom version to attend one of our live classes.
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This is the same set up that you will see for the deep dive
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and we have these three phones directly attached to the rack.
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Now, if you’re renting rack time, they’re physically attached to the rack.
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If you’re in one of our live classes or here in the deep dive,
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they are actually in front of you so they’re miles away,
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thousands of miles away possibly from the actual rack.
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However, they still look through layer two tunnelling
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like they’re directly attached to the rack,
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but they’re not directly attached, it is actually layer to tunnelling.
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A reason I’ve point this out is this is actually the way
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that you will be tested in the real lab.
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Even if in your in San Jose and every other site,
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all of the hardwares in San Jose but even San Jose
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has the same set up where all of the phones
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are not directly physically attached to the rack.
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They are actually layered too tunnelled so they look like,
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to CDP, they look like they’re attached to the Branch 1 switch,
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sorry, the Corporate Head Quarter switch, the main site,
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or the branch1 site attached to the Ethernet switch module,
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or the Branch 2 site attached to in the real lab.
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Probably, another Ethernet switch module but here we have a 3550 switch
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which are not responsible for configuring but however it is,
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they are totally configured for you and that’s where phones are attached.
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So, that’s how they look like they’re attached.
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At our Branch 2 site, we have VLAN11
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that’s being used for voice and 12 that’s used for data.
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So, let’s go ahead and minimize that and VLAN11 maps to Fa00.11.
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Let’s do a show run interface Fa00.11 and then also .12.
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We see that we’ve got interface .11 actually maps to 82.1.
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I’m sorry, 82.1q encapsulation trunking to VLAN11
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and that is the voice VLAN and it’s one 177.3.11.1/24
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just as we’re told to set up a DHCP pool for our look back 0
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which is gonna be used for TFTP is 177.1.2.54.3.
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So, let’s go ahead and for our task, jump in to config T.
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We wanna do our IPDHCP excluded address pool before
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we actually create the pool itself.
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So, 177.3.11.1 is the low address.
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The high address is 177.3.11.20 and that should do it.
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Now, we’ll create an IPDHCP pool and we’ll call it CME phones.
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We’ll say a network address,
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network address of 177.3.11.0 with a /24
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or we could use 255.255.255.0
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and we've got option 150 for TFTP.
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We’re gonna use IP and best to just copy and paste.
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And of course the default router of 177.3.11.1,
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and that’s really all we should need.
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Our phones should be able to get DHCP now.
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I’ll go ahead and reset them although you can’t see them just yet.
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I’ll actually go and tell them to **#**.
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So all three of them will reset.
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Let’s go ahead and actually bring up Switch 2 as well,
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so that we can do a show CDP neighbor
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and see these three phones attached.
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Now, they all look like they’re attached to the same port,
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and of course they aren’t, but again they’re mapped layer two tunnel that over.
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We should shortly be able to do show IPDHCP bindings.
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And we see that two of them have IP addresses so far.
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So, with DHCP, it adds on a 01,
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has a client identifier so that is not part of the MAC address.
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This is actually the MAC address portion.
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So BAAE, there’s one of the phones last for D7BD.
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Here’s the other phone. So we’re still waiting on 1A93.
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To get an IP address, let's see which one of those that is.
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When you know it, it’s the cantankerous SIP phone.
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We’ll check back in a little bit and see if that’s got an IP address.
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We’re not gonna sit here and wait for it
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just because the SIP phone can be a little cantankerous as well.
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I’ll give it a second here to reboot after I resend it the second time.
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Show IPDHCP binding.
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Two of them have IP addresses.
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You can do a debug IPDHCP server.
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Make sure we’ve turned them on.
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There you go. There is 1A93.
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Now, we don’t need to use anything like IP helper address
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because the router is listening to the broadcast
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from that locally connected subnet.
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Here we go and here's the, I might go ahead and undebug all.
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Here’s the notification of the discoverer from the address ending in 1A93.
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We’re adding it to a radix tree, the # tree
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and we’re assigning the IP address of .23 with handed out .21 and 2.
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Now, we’re handing out .23 to the client.
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This includes the client identifier.
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So, it’s got IP address.
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We should now be able to do show IP DHCP binding
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and all three of them should have IP addresses now.
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I’ll just verify that real briefly here.
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We got .22 on this phone,
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.23 on that phone and that’s a wrong button. Yes, .21.
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So, all of them have their IP addresses assigned and life is good.
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