WEBVTT 1 00:00:00.000 --> 00:00:00.780 foreign [Music] 2 00:00:00.780 --> 00:00:28.500 I'm Dr Mann and I'd like to welcome you to this Security Plus certification exam review 3 00:00:29.460 --> 00:00:35.040 and we're going to take the topic tonight networking basics 4 00:00:35.880 --> 00:00:39.420 and we're going to go ahead and start with this first question on web servers 5 00:00:40.800 --> 00:00:45.120 a website that you have been trying to serve has been taking a while to load and 6 00:00:45.120 --> 00:00:50.880 is very laggy due to the large amount of HTTP requests that are being sent to the web server 7 00:00:51.540 --> 00:00:57.420 which of the following would be the best course of action to improve the current and future 8 00:00:57.420 --> 00:01:03.840 web server performance take a moment look at the responses and then let's see what you're thinking 9 00:01:07.620 --> 00:01:17.100 okay so we got responses coming in the chat with a lot of votes or Choice number B or Choice letter b 10 00:01:19.380 --> 00:01:28.260 um so if we look at these answer choices adding more RAM clearly does not help the situation 11 00:01:29.460 --> 00:01:36.360 the one that most people have chosen had a second identical web server plus a load 12 00:01:36.360 --> 00:01:43.980 balancer in front to spread out incoming HTTP connections across that is the correct answer 13 00:01:45.360 --> 00:01:53.640 so load balancers typically placed in the DMZ generally used to load balance requests to web 14 00:01:53.640 --> 00:02:03.060 applications but they can also be found inside the network um let's see yeah which the phone 15 00:02:03.060 --> 00:02:10.560 would be the best course of action to improve the current and future performance so configuring SSL 16 00:02:10.560 --> 00:02:17.040 on the web server to filter incoming is not going to help us configuring a router between 17 00:02:17.040 --> 00:02:27.600 the web server and the default gateway not going to help us either so the correct answer is B okay 18 00:02:34.740 --> 00:02:35.640 next question 19 00:02:40.440 --> 00:02:45.060 which of the following is true regarding IPv6 addresses 20 00:02:48.420 --> 00:02:54.480 okay and a lot of votes for D it looks like all options are correct 21 00:02:55.860 --> 00:03:04.980 okay so if we look at these choices um IPv6 addresses are written using hex notation 22 00:03:08.580 --> 00:03:13.320 the first 64 bits contain the host's interface ID 23 00:03:17.760 --> 00:03:23.820 maybe that could depend on which way you are looking at the address 24 00:03:24.900 --> 00:03:31.080 however generally going uh left to right 25 00:03:33.420 --> 00:03:42.660 that will not be the host's interface ID okay so let's see 26 00:03:46.200 --> 00:03:49.860 okay take a look at this example address 27 00:03:52.260 --> 00:04:01.920 what you see highlighted in yellow is the site prefix the subnet ID follows in the fourth 28 00:04:01.920 --> 00:04:10.380 segment with quartet if you wish and then the last 64 bits are the host interface ID 29 00:04:13.440 --> 00:04:20.760 so these are backwards and so all options are not correct the correct answer is C 30 00:04:21.420 --> 00:04:24.960 IPv6 addresses are written using X notation 31 00:04:27.120 --> 00:04:27.620 okay 32 00:04:34.440 --> 00:04:37.080 let's see and the next one 33 00:04:40.620 --> 00:04:47.520 okay you should use the command ping zero colon zero colon zero colon zero colon zero 34 00:04:47.520 --> 00:04:56.160 colon zero colon zero colon one on a Windows 10 server to determine what okay what do you think 35 00:05:03.900 --> 00:05:16.980 okay got responses in the chat we've got votes for a Nazi uh a a a c okay so this is pretty easy 36 00:05:18.360 --> 00:05:26.760 um I I think it's pretty clear that this is not nor does it look anything like an ip4 address 37 00:05:27.600 --> 00:05:39.720 so right away we can eliminate choices C and D okay um so that leaves A and B excuse me 38 00:05:41.400 --> 00:05:48.960 and so basically we are looking to determine if the local ipv stack is functioning 39 00:05:50.100 --> 00:05:57.060 so the question for you how else could you see this written 40 00:06:05.160 --> 00:06:07.440 okay so we have a response 41 00:06:09.060 --> 00:06:14.220 repeat the question yes how else could we see the command given in the question written 42 00:06:16.800 --> 00:06:26.100 it's this seems fairly cumbersome to write out ping zero colon zero colon zero colon zero Etc 43 00:06:30.480 --> 00:06:38.160 painting localhost okay how about if we were going to use IPv6 address 44 00:06:39.960 --> 00:06:53.100 notation okay double colon as in ping colon colon one okay so remember that 45 00:06:54.540 --> 00:07:03.840 we can use leading zero suppression and consecutive quartets or segments of all 46 00:07:03.840 --> 00:07:11.820 zeros can be eliminated and replaced with the double colon okay let's go on to the next question 47 00:07:22.500 --> 00:07:28.620 which IPv6 address is used for link local unicasts 48 00:07:37.200 --> 00:07:42.600 okay we've got some responses coming in the chat and remember as you're 49 00:07:42.600 --> 00:07:48.360 looking at answers or questions look for things that you can easily eliminate 50 00:07:51.900 --> 00:07:54.720 and so far we have one response 51 00:07:59.940 --> 00:08:06.120 okay so we have one vote for Choice D anybody else 52 00:08:06.960 --> 00:08:11.160 wanting to weigh in before we give out the answer on this one 53 00:08:14.220 --> 00:08:18.240 is there anything that looks obviously incorrect 54 00:08:24.000 --> 00:08:31.140 okay yes a very good so this is the unspecified address 55 00:08:32.220 --> 00:08:39.480 or the representation which indicates the absence of an address and cannot be assigned to a host 56 00:08:40.920 --> 00:08:49.740 okay um if you look at colon colon one and think about from the last question 57 00:08:50.520 --> 00:09:02.700 that's localhost and then ff00 colon colon slash eight represents the IPv6 multicast 58 00:09:03.660 --> 00:09:15.000 the correct answer is Choice d Fe 80 colon colon slash 10. okay this is link local 59 00:09:17.700 --> 00:09:20.040 okay moving on 60 00:09:27.840 --> 00:09:31.140 what can I see MP be used for 61 00:09:45.060 --> 00:09:52.260 yeah all right let's see what's in the chat we have lots of responses coming in and 62 00:09:53.940 --> 00:10:06.240 looks like Choice d is um because everyone's selection here okay so all options are correct 63 00:10:07.260 --> 00:10:10.140 and choice D is the correct answer 64 00:10:11.160 --> 00:10:20.640 so you can report ipv4 errors and Status IPv6 errors and status and this protocol supports the 65 00:10:20.640 --> 00:10:29.040 function of troubleshooting utilities such as ping and trace route these are all correct answers okay 66 00:10:31.740 --> 00:10:37.500 all right and so what does icmp stand for 67 00:10:40.920 --> 00:10:48.240 internet control message protocol yes it does very good all right let's move on to the next question 68 00:10:54.000 --> 00:10:54.500 okay 69 00:10:56.580 --> 00:10:59.940 okay identify all things wrong with this load 70 00:10:59.940 --> 00:11:03.720 balancer diagram okay so let's bring up the diagram 71 00:11:09.540 --> 00:11:11.040 let's see here 72 00:11:18.120 --> 00:11:22.980 okay everybody can see this okay yes 73 00:11:26.760 --> 00:11:27.260 okay 74 00:11:31.260 --> 00:11:35.880 all right great so let's take a moment look at this 75 00:11:40.200 --> 00:11:49.740 and so our answer choices I'm going to read these to you as we're looking at the diagram 76 00:11:51.120 --> 00:11:58.620 the first answer choice and by the way for this question we are supposed to choose all that apply 77 00:12:00.240 --> 00:12:07.680 Okay so Choice a load balancer is using a link local address 78 00:12:13.320 --> 00:12:19.620 Choice B the left-hand web server IP is invalid 79 00:12:22.320 --> 00:12:36.600 Choice C the middle web server IP is invalid and choice D the right hand web server IP is invalid 80 00:12:39.420 --> 00:12:47.100 okay so once again our four answer choices are the load balancer is using a link local address 81 00:12:48.660 --> 00:12:55.140 the web server to the left has a an invalid IP 82 00:12:56.580 --> 00:13:03.720 the one in the middle has an invalid IP and the one on the right has an invalid IP okay 83 00:13:08.040 --> 00:13:08.820 what do you think 84 00:13:15.660 --> 00:13:23.640 okay so we have a couple of answers in the in the chat let's get a couple more before we open it up 85 00:13:32.460 --> 00:13:48.420 okay so we have three responses a a b d c is incorrect okay all right so the load balancer 86 00:13:48.420 --> 00:13:53.580 is using a link local address and that's a problem we would need a public address 87 00:13:55.260 --> 00:14:00.240 okay Fe 80 is linked local 88 00:14:02.640 --> 00:14:05.400 what about the web server on the left here 89 00:14:07.440 --> 00:14:10.920 does anybody know what's wrong with this IPv6 address 90 00:14:14.220 --> 00:14:21.540 this is the one that reads two zero zero one colon colon c8o colon colon f82 91 00:14:24.360 --> 00:14:30.420 so what's wrong with that is missing the last part of one part of the address 92 00:14:32.640 --> 00:14:40.440 okay so you think it's missing something yes okay anybody else 93 00:14:48.360 --> 00:14:55.020 okay well the this is definitely a problem and the reason is that you cannot use 94 00:14:55.020 --> 00:15:00.360 the double colon replacement twice in the same IPv6 address 95 00:15:02.760 --> 00:15:08.460 okay how about the web server in the middle does anybody know what's 96 00:15:08.460 --> 00:15:18.420 wrong with this IPv6 address it has two wrong lettuce okay that's gone too far 97 00:15:19.140 --> 00:15:28.680 gone too far yes that is absolutely correct and those letters are n and G okay so in 98 00:15:28.680 --> 00:15:35.820 hexadecimal notation we use the characters zero through nine and the letters a who f 99 00:15:36.660 --> 00:15:44.820 okay and finally uh the server the web server on the right what's wrong with that address 100 00:15:54.780 --> 00:15:59.940 this may be the trickiest answer of the poor 101 00:16:05.940 --> 00:16:11.340 okay so I would direct your attention to the very last quartet 102 00:16:16.380 --> 00:16:24.780 how many characters I mean sure this last quartet or segment whichever you prefer 103 00:16:25.620 --> 00:16:36.540 F eight two two one okay so there's one too many hex characters there right there can only be four 104 00:16:38.820 --> 00:16:43.080 um to me this is kind of like if you've seen those 105 00:16:44.400 --> 00:16:50.940 um I don't know what they are puzzles maybe where you know they you're asked to read a statement 106 00:16:51.900 --> 00:16:56.700 you know asked what's wrong with it and it's one of those situations where they put the 107 00:16:56.700 --> 00:17:06.420 word uh in twice and unless you've seen it a lot most people just miss it and read right over it 108 00:17:07.980 --> 00:17:14.100 um I think maybe that's why the two twos consecutive twos are there so kind of fools 109 00:17:14.100 --> 00:17:22.140 your eye okay and too many characters in the last segment yes okay so the correct answer here 110 00:17:24.900 --> 00:17:33.240 is all four answers identify something wrong with that load balancer diagram 111 00:17:35.160 --> 00:17:38.400 okay let's go on to the next question 112 00:17:45.260 --> 00:17:46.260 [Music] 113 00:17:46.260 --> 00:17:49.260 okay here we go all right 114 00:17:52.260 --> 00:17:57.300 you need to implement a load balancer scheduling algorithm 115 00:17:57.960 --> 00:18:06.600 to evenly spread active user sessions across all web hosts which one should you choose 116 00:18:14.700 --> 00:18:15.200 okay 117 00:18:18.180 --> 00:18:29.700 okay so it looks like we've got a vote for d and a few votes for a okay so 118 00:18:34.320 --> 00:18:43.500 let me see uh uh eggs yeah mostly so most people are right now are selecting answer Choice a 119 00:18:45.360 --> 00:18:47.400 um and that is not correct 120 00:18:50.520 --> 00:18:53.220 anybody else want to weigh in before we go over this 121 00:19:06.240 --> 00:19:09.120 Okay so 122 00:19:11.580 --> 00:19:23.340 um with a round robin um algorithm it's absolutely one of the simplest and as client requests come in 123 00:19:23.340 --> 00:19:35.340 they're basically distributed one after the other to each server okay and weighted round robin is 124 00:19:35.340 --> 00:19:42.840 kind of the same thing except certain resources have weights assigned to them and they're going 125 00:19:42.840 --> 00:19:51.960 to be based on things like their processing power okay and random yeah that's I would 126 00:19:51.960 --> 00:19:58.800 say that's the the obviously incorrect answer but the correct answer here is the least connections 127 00:20:00.600 --> 00:20:08.760 and in lease connections load balancing takes into account the current number of active connections 128 00:20:09.540 --> 00:20:17.580 on each server the load balancer forwards the new request to the server that is currently serving 129 00:20:17.580 --> 00:20:28.320 up the lowest number of active connections okay so that is the correct answer for this question 130 00:20:30.540 --> 00:20:33.600 all right let's go on to the next question 131 00:20:45.000 --> 00:20:52.200 your it manager says that your company's website ordering system has a single point of failure in 132 00:20:52.200 --> 00:21:03.540 the single load balancer then continues to suggest configuring two load balancers where only one at a 133 00:21:03.540 --> 00:21:12.180 time is in service what type of load balancing configuration has your it manager suggested 134 00:21:13.440 --> 00:21:17.820 okay take a moment look at your choices and make a selection 135 00:21:29.400 --> 00:21:35.880 okay all right we've got some responses coming in let's see what you're thinking 136 00:21:38.340 --> 00:21:48.000 okay so we have a lot of votes for Choice D active passive and this is the correct answer 137 00:21:49.500 --> 00:21:59.760 active active is a configuration where both load balancers are online okay round robin and least 138 00:21:59.760 --> 00:22:09.480 connections doesn't exactly apply to this and so active passive is what we're looking for and 139 00:22:10.260 --> 00:22:19.200 with active passive one load balancer handles the work until there's a problem 140 00:22:20.280 --> 00:22:32.820 and when there's a problem the standby load balancer notices this and takes over the work okay 141 00:22:36.000 --> 00:22:37.500 let's go on to the next question 142 00:22:49.260 --> 00:22:55.140 if your standby load balancer determines that the primary load balancer is down 143 00:22:56.100 --> 00:23:02.220 and you are operating on an active passive load balancer configuration 144 00:23:02.940 --> 00:23:07.560 what attribute would your standby load balancer take control of 145 00:23:14.400 --> 00:23:17.340 okay so as you look at the answer choices 146 00:23:18.720 --> 00:23:25.860 um it's pretty clear that we're looking for either a MAC address or an IP address 147 00:23:27.900 --> 00:23:30.720 so which do you think that would be 148 00:23:34.380 --> 00:23:37.020 IP address okay that is correct 149 00:23:37.680 --> 00:23:47.940 all right so we can eliminate the answer choices A and B and that leaves choices C and D 150 00:23:50.400 --> 00:23:59.760 okay let's see if we have any yeah we have a couple of votes for C load balancer IP address 151 00:23:59.760 --> 00:24:07.380 and that is correct um so in both active active and active passive configurations 152 00:24:09.120 --> 00:24:15.120 um the load balancer has an IP address assigned and we may know this or it's 153 00:24:15.120 --> 00:24:22.140 also known as the virtual IP and so clients are configured to send requests to the virtual IP 154 00:24:22.140 --> 00:24:31.260 address assigned to the load balancer okay all right let's go on to the next question 155 00:24:38.160 --> 00:24:43.020 an I.T specialist for a public-facing web application 156 00:24:43.860 --> 00:24:50.820 wants to lessen the amount of processing that each back-end server pool has 157 00:24:52.020 --> 00:25:01.380 if they are using a back-end Windows server configured in a load balancer and https is 158 00:25:01.380 --> 00:25:11.160 already configured on each server what should the IT specialist do let me take a moment 159 00:25:11.160 --> 00:25:15.600 and look at your responses and then we'll see what you're thinking on this question 160 00:25:24.900 --> 00:25:37.260 okay so we have some responses vote for c one per B Okay so Choice number C or letter C excuse me 161 00:25:38.040 --> 00:25:44.160 Choice C generate a new certificate is not really going to do anything to help 162 00:25:44.160 --> 00:25:52.620 reduce the amount of processing on the back end server pool so C is incorrect 163 00:25:55.680 --> 00:25:57.840 okay we 164 00:26:02.520 --> 00:26:09.780 okay so the correct answer here is B and that is to configure SSL TLS 165 00:26:09.780 --> 00:26:16.860 termination at the load balancer Choice a says configure ipsec on the load balancer 166 00:26:16.860 --> 00:26:23.520 ipsec operates at the network layer of the OSI model which is responsible for 167 00:26:23.520 --> 00:26:29.640 routing data packets and SSL operates at the application layer of the OSI model 168 00:26:33.000 --> 00:26:42.120 configuring SSL TLS termination at the load balancer this should be the way to handle this 169 00:26:42.120 --> 00:26:49.620 to handle SSL encryption decryption so the traffic between the load balancer and the backend server 170 00:26:50.220 --> 00:26:58.860 is then in H or represented as http SSL should terminate at the load balancer 171 00:26:58.860 --> 00:27:05.820 because it offers a centralized location to correct SSL or tax 172 00:27:07.860 --> 00:27:15.300 and in order to perform deep packet inspection SSL must be terminated at the load balancer or earlier 173 00:27:15.900 --> 00:27:21.420 but traffic between the load balancer and the application servers would be unencrypted 174 00:27:21.420 --> 00:27:27.180 and that's really what's going to get you the Improvement in processing in 175 00:27:27.180 --> 00:27:35.580 the amount of processing the last choice of using or enabling SSL TLS pass through 176 00:27:36.420 --> 00:27:44.580 and so SSL passed through basically passes data through a load balancer to the server 177 00:27:44.580 --> 00:27:54.540 without decrypting it so that really doesn't help us so the correct answer here is 80. 178 00:27:57.360 --> 00:27:57.900 okay 179 00:28:00.960 --> 00:28:01.740 next question 180 00:28:06.300 --> 00:28:13.620 which of the following is not true regarding OSI layers with load balancers 181 00:28:22.500 --> 00:28:32.220 okay right so we have a response in the chat no idea okay all right so let's take a little 182 00:28:32.220 --> 00:28:41.340 information about persistence and affinity um session persistence means that a user's requests 183 00:28:41.340 --> 00:28:50.340 are consistently handled by the same server or node during a session and session Affinity 184 00:28:50.340 --> 00:29:01.860 means that the requests are preferably handled by the same server or node but not necessarily okay 185 00:29:04.320 --> 00:29:06.420 So based on that information 186 00:29:09.420 --> 00:29:12.840 does that help you come to an answer choice 187 00:29:18.780 --> 00:29:22.020 exactly okay exactly 188 00:29:25.980 --> 00:29:28.980 all right so which of the following is not true then 189 00:29:32.580 --> 00:29:35.160 or are all answer choices true 190 00:29:40.080 --> 00:29:40.740 okay 191 00:29:43.140 --> 00:29:49.980 so all right let's see what we have in the chat here I'm going to explain one more time sure 192 00:29:50.820 --> 00:29:59.940 okay so again session persistence means that a user's requests are consistently handled 193 00:30:00.600 --> 00:30:04.020 by the same server or node during a session 194 00:30:05.700 --> 00:30:16.440 affinity means that they are preferably handled by the same server but it's not necessarily true 195 00:30:21.360 --> 00:30:33.300 Okay so based on this um first of all affinity can be considered an OSI layer or approach 196 00:30:34.020 --> 00:30:44.400 okay and persistence can be considered a layer 7 approach so these two choices are true 197 00:30:47.040 --> 00:30:55.920 the real question is here in Choice C the statement Affinity is more reliable than 198 00:30:55.920 --> 00:31:02.820 persistence now remember persistence is associated with the same node 199 00:31:03.480 --> 00:31:11.580 affinity means that I would like that condition to exist but it may not necessarily be true 200 00:31:19.140 --> 00:31:28.020 So based on what we've said about persistence and Affinity okay we have answer D okay 201 00:31:29.100 --> 00:31:35.160 and another vote for d and no the correct answer is C 202 00:31:36.180 --> 00:31:44.280 affinity is more reliable than persistence this is the statement that is not true okay 203 00:31:47.460 --> 00:31:49.980 all right so 204 00:31:52.020 --> 00:32:03.000 while both have advantages typically persistence is more reliable than session Affinity because 205 00:32:03.000 --> 00:32:08.160 it ensures that all requests from a client are handled by the same server 206 00:32:09.540 --> 00:32:12.960 so this is the best answer for this question 207 00:32:15.660 --> 00:32:26.400 okay um there can be a little bit of confusion sometimes between the terms persistence and 208 00:32:26.400 --> 00:32:35.760 affinity um the names however are are fairly good in that if something persists 209 00:32:36.420 --> 00:32:47.580 it stays the same an affinity for something is more like a desire okay so this this definitely 210 00:32:48.660 --> 00:32:57.300 um is an area of topic study that will help you certainly with this exam um but again I 211 00:32:57.300 --> 00:33:03.900 think it's important that you remember persistence typically means that requests are handled by the 212 00:33:03.900 --> 00:33:12.420 same server Affinity is that you would like that situation to occur but it's not guaranteed okay 213 00:33:15.180 --> 00:33:16.080 next question 214 00:33:22.620 --> 00:33:27.780 which type of load balancing is being depicted in the attached image 215 00:33:28.680 --> 00:33:35.820 all right so I'd like you to take a moment to look at your choices 216 00:33:38.220 --> 00:33:40.380 and then I'm going to bring up the image 217 00:33:42.540 --> 00:33:48.960 so we can look at that which type of load balancing that's what we are trying to determine 218 00:33:51.000 --> 00:33:51.500 okay 219 00:33:56.820 --> 00:34:03.360 okay so your answer choices are active active least connections random or round robin 220 00:34:04.500 --> 00:34:06.180 and I'm going to bring up the image 221 00:34:17.820 --> 00:34:27.960 okay here's the image web clients client requests enter the network load balancer 222 00:34:28.920 --> 00:34:35.460 you can see the requests are numbered one two three and four and coming out of the 223 00:34:35.460 --> 00:34:43.500 load balancer we see one and three going to the top server and two and four going to the bottom 224 00:34:46.980 --> 00:34:56.040 your choices for which type of load balancing is being presented are active active least 225 00:34:56.040 --> 00:35:05.100 connections random or round robin okay we've got selection of responses in the chat 226 00:35:08.700 --> 00:35:13.620 and it looks pretty much like everybody's saying a for active 227 00:35:13.620 --> 00:35:17.520 active and one vote for least connections okay 228 00:35:19.920 --> 00:35:31.500 all right so client request one enters the load balancer goes to the top two comes in goes to 229 00:35:31.500 --> 00:35:42.840 the bottom three comes in goes to the top four comes in goes to the bottom one two three four 230 00:35:49.560 --> 00:35:53.040 anybody want to uh change their opinion 231 00:35:55.320 --> 00:35:58.740 okay because active active is not the correct answer 232 00:36:01.860 --> 00:36:11.220 so that leaves least connections random and ground Robin of those choices I would say that 233 00:36:11.760 --> 00:36:18.660 this does not look random to me one two three four that does not look random at all 234 00:36:20.340 --> 00:36:28.020 okay and right you've got several votes for round robin and that's exactly what it is okay 235 00:36:31.380 --> 00:36:40.260 all right so round robin is what was being depicted in that image all right can I ask 236 00:36:40.260 --> 00:36:48.600 you a question sure um Palace that scenario so much different from least connections 237 00:36:49.860 --> 00:36:55.440 because the requests have been distributed evenly 238 00:36:56.220 --> 00:37:03.960 and in this sort of round robin fashion so the first one goes to the top server second one goes 239 00:37:03.960 --> 00:37:10.920 the bottom third to the top fourth to the bottom right so we're not looking at who's handling the 240 00:37:10.920 --> 00:37:18.540 least number of connections were simply assigning the request top bottom top bottom top bottom right 241 00:37:19.560 --> 00:37:25.500 and you know it would be the same if you had more servers in fact if you had four 242 00:37:25.500 --> 00:37:34.560 you would see request one two three and four and if another request came in five it would 243 00:37:34.560 --> 00:37:41.040 start back up at the first server again and we would proceed in that manner round robin 244 00:37:42.780 --> 00:37:51.180 so basically iteratively one after the other and that's what they're depicting here okay all right 245 00:37:52.860 --> 00:38:01.800 okay so you know and again it from the load balancers point of view the load balancer 246 00:38:01.800 --> 00:38:10.980 knows about and has say a list for example of servers and then simply goes through them the 247 00:38:10.980 --> 00:38:17.520 list in order sending the requests down the list of servers and then when it gets to the bottom 248 00:38:17.520 --> 00:38:26.100 it just jumps to the top again and starts populating requests in order okay all right 249 00:38:30.360 --> 00:38:31.560 let's go to the next question 250 00:38:39.300 --> 00:38:45.480 okay checking back-end server responsiveness or availability 251 00:38:45.480 --> 00:38:54.540 is the primary purpose of which load balancer option okay take a moment look at your choices 252 00:39:07.140 --> 00:39:15.900 Okay so I have a few responses coming into the chat and as always when you're looking 253 00:39:15.900 --> 00:39:23.880 at questions keep an eye out for something that may stick out as obviously incorrect 254 00:39:25.860 --> 00:39:35.340 so you can eliminate it from the possible choices okay all right let's see what we have in chat 255 00:39:37.380 --> 00:39:47.100 okay so we have a few votes or a Health probe okay 256 00:39:49.440 --> 00:40:01.260 all right so Source IP affinity really doesn't fit and as we mentioned previously 257 00:40:02.940 --> 00:40:09.120 um Affinity is you know were you trying to route a request to the same Target 258 00:40:09.960 --> 00:40:19.500 but it's not guaranteed as opposed to persistence um round robin as we have seen is basically 259 00:40:19.500 --> 00:40:27.840 traversing a list of Targets in order and fixed weight would be a weighted situation 260 00:40:29.280 --> 00:40:35.700 but I don't really think any of those have much to do with responsiveness 261 00:40:35.700 --> 00:40:42.000 or availability and that actually leaves us with the correct answer which is Health probe 262 00:40:42.660 --> 00:40:50.160 and so the health probe is used to determine the status of the instances in the back end pool 263 00:40:51.420 --> 00:40:59.100 during load balancer creation you configure a health probe for the load balancer to use 264 00:41:00.720 --> 00:41:06.420 the help probe will determine if an instance is healthy and can receive traffic 265 00:41:07.680 --> 00:41:12.960 okay so a is the correct answer to this question 266 00:41:16.260 --> 00:41:18.480 all right let's move on to the next question 267 00:41:21.900 --> 00:41:31.440 while using Source IP Affinity in a load balancer configuration when a client establishes 268 00:41:31.440 --> 00:41:39.540 a connection its session becomes blank to the node that first accepted the request 269 00:41:42.840 --> 00:41:45.420 okay all right what do you think 270 00:41:48.420 --> 00:41:49.440 yes good 271 00:41:51.900 --> 00:41:58.020 okay we have a couple of selections I think this one's kind of obvious 272 00:42:05.820 --> 00:42:12.540 okay let's see what you're thinking here uh votes for b as the correct answer 273 00:42:13.500 --> 00:42:23.760 and yeah that is correct Source IP affinity and lost does not fit the statement 274 00:42:25.020 --> 00:42:33.180 detached does not fit the statement uh those two I think are the most obvious to eliminate 275 00:42:34.080 --> 00:42:40.020 Idol yeah really doesn't make sense and knowing what we know about 276 00:42:40.980 --> 00:42:50.460 Source IP affinity bound is the best answer to this question okay let's move on 277 00:42:55.320 --> 00:43:01.920 all right one of your back end servers named www2 278 00:43:01.920 --> 00:43:09.180 is used by a load balancer as one Webhead in a load balanced pool 279 00:43:10.440 --> 00:43:25.020 www.2 has more RAM and CPU processing power than others in the same web pool to ensure it hosts 280 00:43:25.020 --> 00:43:33.540 more client sessions than the others what is the best load balancing algorithm to use 281 00:43:36.420 --> 00:43:42.720 okay take a moment look at the choices and make a selection 282 00:43:47.760 --> 00:43:51.960 okay all right let's see what's in the chat 283 00:43:54.480 --> 00:44:01.200 okay so we have lots of votes for B which is least response 284 00:44:01.800 --> 00:44:11.040 and this is correct okay so the key here is that the um 285 00:44:14.280 --> 00:44:18.480 Webhead or the www.2 286 00:44:19.140 --> 00:44:26.880 has more RAM and processing power than others okay so we know that we 287 00:44:26.880 --> 00:44:31.680 wanted to handle more work because it's going to be more capable of doing this 288 00:44:32.520 --> 00:44:40.620 so this question hinges on the difference between least response and least connections 289 00:44:41.280 --> 00:44:49.560 so starting with Choice C random that's the I would say the obviously incorrect answer 290 00:44:51.000 --> 00:44:57.780 um and understanding that round robin simply just follows a list iteratively in order makes 291 00:44:57.780 --> 00:45:02.820 that unsuitable so it really boils down to least response released connections 292 00:45:03.840 --> 00:45:12.720 and the difference is that at least connections moves um forwards new requests 293 00:45:13.740 --> 00:45:20.400 to the server that's currently servicing the lowest number of active connections 294 00:45:21.060 --> 00:45:30.000 least response takes into account active connections plus the average response time okay 295 00:45:30.660 --> 00:45:40.380 so that gives us that little extra Edge to to determine which you know algorithm 296 00:45:40.380 --> 00:45:45.660 at least in this question is the best and certainly in the reality of the situation 297 00:45:46.920 --> 00:45:53.280 um if you were using that then it's going to choose the more powerful uh 298 00:45:55.200 --> 00:46:02.460 load balancer let me see back when we serves low balancer and Webheads right 299 00:46:02.460 --> 00:46:10.680 okay so we're looking for lowest number of active connections and shortest response time 300 00:46:10.680 --> 00:46:22.140 at shortest shortest average response time okay so the correct answer is B least response okay 301 00:46:26.580 --> 00:46:29.700 all right and now we jump way back up here 302 00:46:32.340 --> 00:46:40.320 okay which of the following are not an advantage from utilizing a load balancer choose to 303 00:46:46.800 --> 00:46:57.360 okay so we got a few responses in the chat uh yeah votes for B and C okay so better app security 304 00:46:58.560 --> 00:47:04.800 and better at Regulatory Compliance these are the correct answers 305 00:47:06.000 --> 00:47:16.080 um really not advantages from utilizing load balancing performance and better availability 306 00:47:18.000 --> 00:47:24.960 so the two that are not are app security and Regulatory Compliance okay 307 00:47:27.660 --> 00:47:35.100 and the next question and this is the last one for this section okay next question 308 00:47:39.780 --> 00:47:46.560 after reviewing the feedback from your customer satisfaction surveys you notice that 309 00:47:46.560 --> 00:47:55.620 the predominant complaints is how saved items in a customer's shopping cart are constantly being lost 310 00:47:56.760 --> 00:48:02.280 what load balancer configuration is a solution to satisfy this complaint 311 00:48:07.440 --> 00:48:15.120 okay all right let's see what's in the chat so we have let's see here 312 00:48:16.680 --> 00:48:24.540 let me see the three five okay lots of votes or a session persistence 313 00:48:25.200 --> 00:48:33.600 and this is the uh correct answer clustering and loop prevention really don't have anything to do 314 00:48:33.600 --> 00:48:41.280 with this and that leaves the two choices as a recession persistence and database synchronization 315 00:48:42.960 --> 00:48:48.540 um they are different concepts uh session persistence as we've discussed refers to the 316 00:48:48.540 --> 00:48:55.560 ability of a system to maintain a user's session data across multiple requests 317 00:48:56.400 --> 00:49:02.700 session data can be stored in memory files databases or other storage systems a database 318 00:49:02.700 --> 00:49:09.300 synchronization refers to the process of keeping two or more databases in sync with each other 319 00:49:10.080 --> 00:49:23.400 so the best answer is session persistence and that ends this topic on networking basics it