foreign [Music]
I'm Dr Mann and I'd like to welcome you to this Security Plus certification exam review
and we're going to take the topic tonight networking basics
and we're going to go ahead and start with this first question on web servers
a website that you have been trying to serve has been taking a while to load and
is very laggy due to the large amount of HTTP requests that are being sent to the web server
which of the following would be the best course of action to improve the current and future
web server performance take a moment look at the responses and then let's see what you're thinking
okay so we got responses coming in the chat with a lot of votes or Choice number B or Choice letter b
um so if we look at these answer choices adding more RAM clearly does not help the situation
the one that most people have chosen had a second identical web server plus a load
balancer in front to spread out incoming HTTP connections across that is the correct answer
so load balancers typically placed in the DMZ generally used to load balance requests to web
applications but they can also be found inside the network um let's see yeah which the phone
would be the best course of action to improve the current and future performance so configuring SSL
on the web server to filter incoming is not going to help us configuring a router between
the web server and the default gateway not going to help us either so the correct answer is B okay
next question
which of the following is true regarding IPv6 addresses
okay and a lot of votes for D it looks like all options are correct
okay so if we look at these choices um IPv6 addresses are written using hex notation
the first 64 bits contain the host's interface ID
maybe that could depend on which way you are looking at the address
however generally going uh left to right
that will not be the host's interface ID okay so let's see
okay take a look at this example address
what you see highlighted in yellow is the site prefix the subnet ID follows in the fourth
segment with quartet if you wish and then the last 64 bits are the host interface ID
so these are backwards and so all options are not correct the correct answer is C
IPv6 addresses are written using X notation
okay
let's see and the next one
okay you should use the command ping zero colon zero colon zero colon zero colon zero
colon zero colon zero colon one on a Windows 10 server to determine what okay what do you think
okay got responses in the chat we've got votes for a Nazi uh a a a c okay so this is pretty easy
um I I think it's pretty clear that this is not nor does it look anything like an ip4 address
so right away we can eliminate choices C and D okay um so that leaves A and B excuse me
and so basically we are looking to determine if the local ipv stack is functioning
so the question for you how else could you see this written
okay so we have a response
repeat the question yes how else could we see the command given in the question written
it's this seems fairly cumbersome to write out ping zero colon zero colon zero colon zero Etc
painting localhost okay how about if we were going to use IPv6 address
notation okay double colon as in ping colon colon one okay so remember that
we can use leading zero suppression and consecutive quartets or segments of all
zeros can be eliminated and replaced with the double colon okay let's go on to the next question
which IPv6 address is used for link local unicasts
okay we've got some responses coming in the chat and remember as you're
looking at answers or questions look for things that you can easily eliminate
and so far we have one response
okay so we have one vote for Choice D anybody else
wanting to weigh in before we give out the answer on this one
is there anything that looks obviously incorrect
okay yes a very good so this is the unspecified address
or the representation which indicates the absence of an address and cannot be assigned to a host
okay um if you look at colon colon one and think about from the last question
that's localhost and then ff00 colon colon slash eight represents the IPv6 multicast
the correct answer is Choice d Fe 80 colon colon slash 10. okay this is link local
okay moving on
what can I see MP be used for
yeah all right let's see what's in the chat we have lots of responses coming in and
looks like Choice d is um because everyone's selection here okay so all options are correct
and choice D is the correct answer
so you can report ipv4 errors and Status IPv6 errors and status and this protocol supports the
function of troubleshooting utilities such as ping and trace route these are all correct answers okay
all right and so what does icmp stand for
internet control message protocol yes it does very good all right let's move on to the next question
okay
okay identify all things wrong with this load
balancer diagram okay so let's bring up the diagram
let's see here
okay everybody can see this okay yes
okay
all right great so let's take a moment look at this
and so our answer choices I'm going to read these to you as we're looking at the diagram
the first answer choice and by the way for this question we are supposed to choose all that apply
Okay so Choice a load balancer is using a link local address
Choice B the left-hand web server IP is invalid
Choice C the middle web server IP is invalid and choice D the right hand web server IP is invalid
okay so once again our four answer choices are the load balancer is using a link local address
the web server to the left has a an invalid IP
the one in the middle has an invalid IP and the one on the right has an invalid IP okay
what do you think
okay so we have a couple of answers in the in the chat let's get a couple more before we open it up
okay so we have three responses a a b d c is incorrect okay all right so the load balancer
is using a link local address and that's a problem we would need a public address
okay Fe 80 is linked local
what about the web server on the left here
does anybody know what's wrong with this IPv6 address
this is the one that reads two zero zero one colon colon c8o colon colon f82
so what's wrong with that is missing the last part of one part of the address
okay so you think it's missing something yes okay anybody else
okay well the this is definitely a problem and the reason is that you cannot use
the double colon replacement twice in the same IPv6 address
okay how about the web server in the middle does anybody know what's
wrong with this IPv6 address it has two wrong lettuce okay that's gone too far
gone too far yes that is absolutely correct and those letters are n and G okay so in
hexadecimal notation we use the characters zero through nine and the letters a who f
okay and finally uh the server the web server on the right what's wrong with that address
this may be the trickiest answer of the poor
okay so I would direct your attention to the very last quartet
how many characters I mean sure this last quartet or segment whichever you prefer
F eight two two one okay so there's one too many hex characters there right there can only be four
um to me this is kind of like if you've seen those
um I don't know what they are puzzles maybe where you know they you're asked to read a statement
you know asked what's wrong with it and it's one of those situations where they put the
word uh in twice and unless you've seen it a lot most people just miss it and read right over it
um I think maybe that's why the two twos consecutive twos are there so kind of fools
your eye okay and too many characters in the last segment yes okay so the correct answer here
is all four answers identify something wrong with that load balancer diagram
okay let's go on to the next question
[Music]
okay here we go all right
you need to implement a load balancer scheduling algorithm
to evenly spread active user sessions across all web hosts which one should you choose
okay
okay so it looks like we've got a vote for d and a few votes for a okay so
let me see uh uh eggs yeah mostly so most people are right now are selecting answer Choice a
um and that is not correct
anybody else want to weigh in before we go over this
Okay so
um with a round robin um algorithm it's absolutely one of the simplest and as client requests come in
they're basically distributed one after the other to each server okay and weighted round robin is
kind of the same thing except certain resources have weights assigned to them and they're going
to be based on things like their processing power okay and random yeah that's I would
say that's the the obviously incorrect answer but the correct answer here is the least connections
and in lease connections load balancing takes into account the current number of active connections
on each server the load balancer forwards the new request to the server that is currently serving
up the lowest number of active connections okay so that is the correct answer for this question
all right let's go on to the next question
your it manager says that your company's website ordering system has a single point of failure in
the single load balancer then continues to suggest configuring two load balancers where only one at a
time is in service what type of load balancing configuration has your it manager suggested
okay take a moment look at your choices and make a selection
okay all right we've got some responses coming in let's see what you're thinking
okay so we have a lot of votes for Choice D active passive and this is the correct answer
active active is a configuration where both load balancers are online okay round robin and least
connections doesn't exactly apply to this and so active passive is what we're looking for and
with active passive one load balancer handles the work until there's a problem
and when there's a problem the standby load balancer notices this and takes over the work okay
let's go on to the next question
if your standby load balancer determines that the primary load balancer is down
and you are operating on an active passive load balancer configuration
what attribute would your standby load balancer take control of
okay so as you look at the answer choices
um it's pretty clear that we're looking for either a MAC address or an IP address
so which do you think that would be
IP address okay that is correct
all right so we can eliminate the answer choices A and B and that leaves choices C and D
okay let's see if we have any yeah we have a couple of votes for C load balancer IP address
and that is correct um so in both active active and active passive configurations
um the load balancer has an IP address assigned and we may know this or it's
also known as the virtual IP and so clients are configured to send requests to the virtual IP
address assigned to the load balancer okay all right let's go on to the next question
an I.T specialist for a public-facing web application
wants to lessen the amount of processing that each back-end server pool has
if they are using a back-end Windows server configured in a load balancer and https is
already configured on each server what should the IT specialist do let me take a moment
and look at your responses and then we'll see what you're thinking on this question
okay so we have some responses vote for c one per B Okay so Choice number C or letter C excuse me
Choice C generate a new certificate is not really going to do anything to help
reduce the amount of processing on the back end server pool so C is incorrect
okay we
okay so the correct answer here is B and that is to configure SSL TLS
termination at the load balancer Choice a says configure ipsec on the load balancer
ipsec operates at the network layer of the OSI model which is responsible for
routing data packets and SSL operates at the application layer of the OSI model
configuring SSL TLS termination at the load balancer this should be the way to handle this
to handle SSL encryption decryption so the traffic between the load balancer and the backend server
is then in H or represented as http SSL should terminate at the load balancer
because it offers a centralized location to correct SSL or tax
and in order to perform deep packet inspection SSL must be terminated at the load balancer or earlier
but traffic between the load balancer and the application servers would be unencrypted
and that's really what's going to get you the Improvement in processing in
the amount of processing the last choice of using or enabling SSL TLS pass through
and so SSL passed through basically passes data through a load balancer to the server
without decrypting it so that really doesn't help us so the correct answer here is 80.
okay
next question
which of the following is not true regarding OSI layers with load balancers
okay right so we have a response in the chat no idea okay all right so let's take a little
information about persistence and affinity um session persistence means that a user's requests
are consistently handled by the same server or node during a session and session Affinity
means that the requests are preferably handled by the same server or node but not necessarily okay
So based on that information
does that help you come to an answer choice
exactly okay exactly
all right so which of the following is not true then
or are all answer choices true
okay
so all right let's see what we have in the chat here I'm going to explain one more time sure
okay so again session persistence means that a user's requests are consistently handled
by the same server or node during a session
affinity means that they are preferably handled by the same server but it's not necessarily true
Okay so based on this um first of all affinity can be considered an OSI layer or approach
okay and persistence can be considered a layer 7 approach so these two choices are true
the real question is here in Choice C the statement Affinity is more reliable than
persistence now remember persistence is associated with the same node
affinity means that I would like that condition to exist but it may not necessarily be true
So based on what we've said about persistence and Affinity okay we have answer D okay
and another vote for d and no the correct answer is C
affinity is more reliable than persistence this is the statement that is not true okay
all right so
while both have advantages typically persistence is more reliable than session Affinity because
it ensures that all requests from a client are handled by the same server
so this is the best answer for this question
okay um there can be a little bit of confusion sometimes between the terms persistence and
affinity um the names however are are fairly good in that if something persists
it stays the same an affinity for something is more like a desire okay so this this definitely
um is an area of topic study that will help you certainly with this exam um but again I
think it's important that you remember persistence typically means that requests are handled by the
same server Affinity is that you would like that situation to occur but it's not guaranteed okay
next question
which type of load balancing is being depicted in the attached image
all right so I'd like you to take a moment to look at your choices
and then I'm going to bring up the image
so we can look at that which type of load balancing that's what we are trying to determine
okay
okay so your answer choices are active active least connections random or round robin
and I'm going to bring up the image
okay here's the image web clients client requests enter the network load balancer
you can see the requests are numbered one two three and four and coming out of the
load balancer we see one and three going to the top server and two and four going to the bottom
your choices for which type of load balancing is being presented are active active least
connections random or round robin okay we've got selection of responses in the chat
and it looks pretty much like everybody's saying a for active
active and one vote for least connections okay
all right so client request one enters the load balancer goes to the top two comes in goes to
the bottom three comes in goes to the top four comes in goes to the bottom one two three four
anybody want to uh change their opinion
okay because active active is not the correct answer
so that leaves least connections random and ground Robin of those choices I would say that
this does not look random to me one two three four that does not look random at all
okay and right you've got several votes for round robin and that's exactly what it is okay
all right so round robin is what was being depicted in that image all right can I ask
you a question sure um Palace that scenario so much different from least connections
because the requests have been distributed evenly
and in this sort of round robin fashion so the first one goes to the top server second one goes
the bottom third to the top fourth to the bottom right so we're not looking at who's handling the
least number of connections were simply assigning the request top bottom top bottom top bottom right
and you know it would be the same if you had more servers in fact if you had four
you would see request one two three and four and if another request came in five it would
start back up at the first server again and we would proceed in that manner round robin
so basically iteratively one after the other and that's what they're depicting here okay all right
okay so you know and again it from the load balancers point of view the load balancer
knows about and has say a list for example of servers and then simply goes through them the
list in order sending the requests down the list of servers and then when it gets to the bottom
it just jumps to the top again and starts populating requests in order okay all right
let's go to the next question
okay checking back-end server responsiveness or availability
is the primary purpose of which load balancer option okay take a moment look at your choices
Okay so I have a few responses coming into the chat and as always when you're looking
at questions keep an eye out for something that may stick out as obviously incorrect
so you can eliminate it from the possible choices okay all right let's see what we have in chat
okay so we have a few votes or a Health probe okay
all right so Source IP affinity really doesn't fit and as we mentioned previously
um Affinity is you know were you trying to route a request to the same Target
but it's not guaranteed as opposed to persistence um round robin as we have seen is basically
traversing a list of Targets in order and fixed weight would be a weighted situation
but I don't really think any of those have much to do with responsiveness
or availability and that actually leaves us with the correct answer which is Health probe
and so the health probe is used to determine the status of the instances in the back end pool
during load balancer creation you configure a health probe for the load balancer to use
the help probe will determine if an instance is healthy and can receive traffic
okay so a is the correct answer to this question
all right let's move on to the next question
while using Source IP Affinity in a load balancer configuration when a client establishes
a connection its session becomes blank to the node that first accepted the request
okay all right what do you think
yes good
okay we have a couple of selections I think this one's kind of obvious
okay let's see what you're thinking here uh votes for b as the correct answer
and yeah that is correct Source IP affinity and lost does not fit the statement
detached does not fit the statement uh those two I think are the most obvious to eliminate
Idol yeah really doesn't make sense and knowing what we know about
Source IP affinity bound is the best answer to this question okay let's move on
all right one of your back end servers named www2
is used by a load balancer as one Webhead in a load balanced pool
www.2 has more RAM and CPU processing power than others in the same web pool to ensure it hosts
more client sessions than the others what is the best load balancing algorithm to use
okay take a moment look at the choices and make a selection
okay all right let's see what's in the chat
okay so we have lots of votes for B which is least response
and this is correct okay so the key here is that the um
Webhead or the www.2
has more RAM and processing power than others okay so we know that we
wanted to handle more work because it's going to be more capable of doing this
so this question hinges on the difference between least response and least connections
so starting with Choice C random that's the I would say the obviously incorrect answer
um and understanding that round robin simply just follows a list iteratively in order makes
that unsuitable so it really boils down to least response released connections
and the difference is that at least connections moves um forwards new requests
to the server that's currently servicing the lowest number of active connections
least response takes into account active connections plus the average response time okay
so that gives us that little extra Edge to to determine which you know algorithm
at least in this question is the best and certainly in the reality of the situation
um if you were using that then it's going to choose the more powerful uh
load balancer let me see back when we serves low balancer and Webheads right
okay so we're looking for lowest number of active connections and shortest response time
at shortest shortest average response time okay so the correct answer is B least response okay
all right and now we jump way back up here
okay which of the following are not an advantage from utilizing a load balancer choose to
okay so we got a few responses in the chat uh yeah votes for B and C okay so better app security
and better at Regulatory Compliance these are the correct answers
um really not advantages from utilizing load balancing performance and better availability
so the two that are not are app security and Regulatory Compliance okay
and the next question and this is the last one for this section okay next question
after reviewing the feedback from your customer satisfaction surveys you notice that
the predominant complaints is how saved items in a customer's shopping cart are constantly being lost
what load balancer configuration is a solution to satisfy this complaint
okay all right let's see what's in the chat so we have let's see here
let me see the three five okay lots of votes or a session persistence
and this is the uh correct answer clustering and loop prevention really don't have anything to do
with this and that leaves the two choices as a recession persistence and database synchronization
um they are different concepts uh session persistence as we've discussed refers to the
ability of a system to maintain a user's session data across multiple requests
session data can be stored in memory files databases or other storage systems a database
synchronization refers to the process of keeping two or more databases in sync with each other
so the best answer is session persistence and that ends this topic on networking basics it