View Full Version : Where are my IT/Networking peeps?!?
I had an interview yesterday out-of-state and one of the panel members was a college professor that taught IT to include Cisco Networking. He presented me with a problem which I will include below in italics. Leaving out his answer as well as mine because I want to see what conclusion you draw. He did the work on a dry-erase board after I gave my answer and did it long-hand... old school. I verified my answer via an app on my phone today so now I'm not sure. It's a new app that I've never used so it could be that I'm using it wrong. At any rate, here's the deets:
Examine the exhibit (picture of E0 and HTTP server with single line connecting)
You have been assigned IP address 145.36.0.0/22
You need to assign the first available host address on the first available subnet to the router's E0 interface and next available host on that subnet to the HTTP server.
Which addresses should you assign? What's the subnet? Which class is it?
So, that's one of the questions. What answers do you get and how do you arrive at those? I liken this sort of thing to the teacher in elementary school who forced you to do math long-hand and now there's 17 calculators everywhere you are whenever you need to do math so that was a wasted 2 years as far as I'm concerned. I demonstrated that I at least had an idea how to get to the proper answer but if you have IP calculators for this exact reason... what's the point? I assert that he was just trying to trip me up but to be truthful my response would be that it's not really necessary to perform the job.
I've had a lot of experience with oral exams and have found that professors don't necessarily care about getting the correct answer, but more about how you tackle a problem. But they get pissed when you try to give them bull$hit answers too, so that's worse than saying you don't know. Sounds like you handled this well.
cfortune
01-05-2013, 20:47
Network/Subnet Address = 145.36.0.0 which is a class B address AKA what you would use to advertise this network to neighboring routers (via OSPF for instance) and will appear as a directly connected network in this particular routers routing table
Assign E0 145.36.0.1 255.255.252.0, though at work I always use the last available IP of the subnet.
Assign HTTP server 145.36.0.2 255.255.252.0, with a gateway of 145.36.0.1
Why such a huge network range for such a small network is what I'd ask lol. 1022 useable addresses for a network containing one host is a bit absurd.
ChadAmberg
01-05-2013, 20:52
That's a subnet of 1024 addresses. Subnet mask 255.255.252.0.
It's in the class B address range technically, but that's actually irrelevant in real life, because no class A or B subnet is used as anything other than sets of small subnets. You can tell he's a professor, saying things that may be technically correct but doesn't work in the real world. Kind of like that 7 layers of networking crap. Every stupid test references it, but nothing uses it, especially TCPIP.
I'd say 145.36.0.1 would be the gateway on the router with 145.36.0.2 on the web server.
Network/Subnet Address = 145.36.0.0 which is a class B address AKA what you would use to advertise this network to neighboring routers (via OSPF for instance) and will appear as a directly connected network in this particular routers routing table
Assign E0 145.36.0.1 255.255.252.0, though at work I always use the last available IP for the subnet.
Assign HTTP server 145.36.0.2 255.255.252.0, with a gateway of 145.36.0.1
Why such a huge network range for such a small network is what I'd ask lol. 1022 useable addresses for a network containing one host is a bit absurd.
So here's the funny part....
I looked it over... took a breath and started talking my way through the problem. He agreed that it was a difficult one and told me to take my time. I was talking about subnet at one point and he asked which class it was to which I replied it was class B. He agreed and confirmed that I was correct to the other two panel members. After some more thinking on it I arrived at the following answer:
First available IP: 145.36.0.1 with a subnet of 255.255.252.0
Second available: 145.36.0.2 with a gateway of 145.36.0.1 and a subnet of 255.255.252.0
....exactly what you just said.
He said I was wrong and asked the other panel members (Head of HR and company President) to borrow the dry erase board in the meeting room to demonstrate how to arrive at the proper answer. He broke down a lot of stuff and in the end he arrived at: 145.36.4.1 and 145.36.4.2.
Now, at first I wasn't going to argue with him in an interview because I was already stressed out enough by other situations (turns out this 'expert' they brought and I have a past and he was the LAST person I thought I would see when I walked in) and the last thing I wanted was to be wrong TWICE if you get my drift. I need to send a thank you email to all three and I plan to double and triple check my answer before I even bring up the topic of being wrong again because if it turns out I was indeed wrong I'd rather that not ever come up again. lol I feel like I was right though and if in my email I give them the correct answer and mention it was indeed the first answer I gave suddenly I look like a friggin genius. I know this is a very delicate subject so that's why I wanted some input from others who are in-the-know.
That's a subnet of 1024 addresses. Subnet mask 255.255.252.0.
It's in the class B address range technically, but that's actually irrelevant in real life, because no class A or B subnet is used as anything other than sets of small subnets. You can tell he's a professor, saying things that may be technically correct but doesn't work in the real world. Kind of like that 7 layers of networking crap. Every stupid test references it, but nothing uses it, especially TCPIP.
I'd say 145.36.0.1 would be the gateway on the router with 145.36.0.2 on the web server.
Mother of god... that was question #2. ROFL!
cfortune
01-05-2013, 21:10
I don't understand how you're given the address space 145.36.0.0/22 and you end up with a first available IP of 145.36.4.1/22
145.36.0.0/22 breaks down as:
Network address: 145.36.0.0/22, granted you don't live in like 1998 or some shit and "ip subnet zero" isn't an option on your Cisco.
Host addresses: 145.36.0.1-145.36.3.254
Broadcast address: 145.36.3.255
145.36.4.1 isn't even a valid address in the address space 145.36.0.0/22.
Teufelhund
01-05-2013, 21:13
Network/Subnet Address = 145.36.0.0 which is a class B address AKA what you would use to advertise this network to neighboring routers (via OSPF for instance) and will appear as a directly connected network in this particular routers routing table
Assign E0 145.36.0.1 255.255.252.0, though at work I always use the last available IP for the subnet.
Assign HTTP server 145.36.0.2 255.255.252.0, with a gateway of 145.36.0.1
Why such a huge network range for such a small network is what I'd ask lol. 1022 useable addresses for a network containing one host is a bit absurd.
This is the correct answer. I cannot imagine why anyone would waste so many addresses at a border router, but practicality is obviously not the object of the question. You got it right in the interview.
tmleadr03
01-05-2013, 21:19
http://justcomedies.com/wp-content/uploads/2012/07/donald-gibb-ogre-revenge-of-the-nerds.jpg
Raul Duke
01-05-2013, 21:23
Sounds like he worded the question poorly. If he was saying the /22 was the used and could not be in that sn, then yes the next available would be 145.36.4.1 and .2. I would have given the same answer as you did with the question worded like that.
If I was doing that hire, seeing you give me the info of the sn that was given to you, that would be good enough for me,
You should have asked him if he can do IPv6 calcs.
Sounds like he worded the question poorly. If he was saying the /22 was the used and could not be in that sn, then yes the next available would be 145.36.4.1 and .2. I would have given the same answer as you did with the question worded like that.
If I was doing that hire, seeing you give me the info of the sn that was given to you, that would be good enough for me,
You should have asked him if he can do IPv6 calcs.
But the fact that he uses the word 'assigned' specifically... couldn't that denote that it was indeed in use?? At this point I think it's coming down to semantics which shouldn't really be a determining factor in an interview for an IT position. I think I did enough to demonstrate I knew what I was doing. I should get my facking gold star!
cfortune
01-05-2013, 21:39
But the fact that he uses the word 'assigned' specifically... couldn't that denote that it was indeed in use?? At this point I think it's coming down to semantics which shouldn't really be a determining factor in an interview for an IT position. I think I did enough to demonstrate I knew what I was doing. I should get my facking gold star!
Maybe he meant you already have /22 of your /16 class B already used. The more I read the original question, the more it makes me think thats what he was getting at. Very poorly worded if you ask me. Also a very dated question. You should have called him crazy for using a router and not a layer 3 switch.
Raul Duke
01-05-2013, 21:40
Like I said, Id give you full points if it was my interview.
To me, as an IT manager, I look for people that can find the answer, not ones that know it all (or think they do).
Maybe he meant you already have /22 of your /16 class B already used. The more I read the original question, the more it makes me think thats what he was getting at. Very poorly worded if you ask me. Also a very dated question. You should have called him crazy for using a router and not a layer 3 switch.
I want to bring it up but I want to make sure I have all my i's dotted and my t's crossed when I question him. Then to decide whether to include him on the clarification or if I keep him out of it and take it directly to the ones in charge of hiring and let them decided if they want to address it with him or not. Hmmm....
Like I said, Id give you full points if it was my interview.
To me, as an IT manager, I look for people that can find the answer, not ones that know it all (or think they do).
That's another thing I told them. I said that I was good at getting the right answer to questions I didn't know for sure using resources like the internet. I'm the first one to say that I don't know everything so I tend to double and triple check my work to various sources. This keeps me out of trouble. Let's face it, there won't ever be a time where I would be in a scenario that this interview put me in... no way to look up the answer or double check my answer to make sure. Kind of unrealistic.
I don't understand how you're given the address space 145.36.0.0/22 and you end up with a first available IP of 145.36.4.1/22
145.36.0.0/22 breaks down as:
Network address: 145.36.0.0/22, granted you don't live in like 1998 or some shit and "ip subnet zero" isn't an option on your Cisco.
Host addresses: 145.36.0.1-145.36.3.254
Broadcast address: 145.36.3.255
145.36.4.1 isn't even a valid address in the address space 145.36.0.0/22.
^^^^This Classless Inter Domain Routing (CIDR)as evidenced by the /22 requires that you break the 4 octets into their respective binary representations and work from the on the 10th binary position from the right (32-22). Since there are only 2 binary positions in the 3rd octet the highest range is xxx.xxx.3.254
EDIT: and technically since this is using CIDR it is NOT a class B address
DeusExMachina
01-05-2013, 23:00
145.36.4.0/22 is the next available subnet if 145.36.0.0/22 is used. Maybe that's what he meant by available.
Because I doubt a professor would call a basic subnetting question "very difficult". It is likely purposefully confusing.
145.36.4.0/22 is the next available subnet if 145.36.0.0/22 is used. Maybe that's what he meant by available.
Because I doubt a professor would call a basic subnetting question "very difficult". It is likely purposefully confusing.
145.36.4.0/22 is not a valid CIDR designation....145.36.4.0 lives under 145.36.0.0/21
Damned...I wish I would have been there...I haven't done this shit in 15 years and I could have made that professor look like an idiot. I frakin HATE companies who bring in so called experts for interviews...all they do is blow smoke and obfuscate reality.
DeusExMachina
01-06-2013, 00:00
145.36.4.0/22 is not a valid CIDR designation....145.36.4.0 lives under 145.36.0.0/21
145.36.4.0/22 is still a valid subnet, and any network a.b.c.0/22 is a valid CIDR address.
145.36.4.0/22 is still a valid subnet, and any network a.b.c.0/22 is a valid CIDR address.
True,,,and 145.36.4.0 would be the next available address range above 145.36.0.0/22
cfortune
01-06-2013, 00:30
What type of equipment do you all work on? I was pretty heavy into Cisco. Then I started my current job and worked as a tier 2 person. We had all ProCurve gear and Palo Alto firewalls. After our network engineer quit, I was given the opportunity to move into his role. Now as soon as equipment ages off, I promptly replace it with Juniper EX series switches. We have 4 of their 40 port 10 gbps switches and probably 20 EX4200 48 port 1 gbps. If you guys haven't tried JunOS, I highly recommend it. Pretty different from Cisco or ProCurve but has some huge advantages.
In JunOS you have a candidate config you can edit and push to the running config. So you can make multiple changes and push them out. On Friday I swung our traffic to a remote site to a different circuit. Was done two minutes after my change window started, with validation. Had everything staged up. You can also rollback to any of your last 50 configs or have it rollback after x amount of time. It's a life saver when working on remote equipment. Tell it to rollback the changes after five minutes if you don't accept them. So if you drop a WAN interface or screw up a route, you wait 5 minutes and your equipment becomes reachable again. Pretty awesome stuff.
Their virtual chassis offering is awesome too. 128 gbps cables connect EX series switches to create a backplane. The switches then act as modules, or as one switch. Making interswitch redundancy a piece if cake.
Palo Alto is some pretty rad stuff too. So much you can do. Gotta love having a 16 port application layer firewall. Does NAT, SSL VPN, IPSec PTP VPN, real time AV, threat prevention, policy based routing, user identification, OSPF, BGP, RIP (lol), virtual routers, packet capturing, user activity reports, and a ton of other stuff. They're pricey though.
/geeking out
You have been assigned IP address 145.36.0.0/22
You need to assign the first available host address on the first available subnet to the router's E0 interface and next available host on that subnet to the HTTP server.
The question (and answer) are trivial - but the questions are also incorrect..
Which addresses should you assign?
The valid host range in that subnet is 145.36.0.1 - 145.36.3.254. So e0 is 145.36.0.1 and the server is 145.36.0.2... Easy enough
What's the subnet?
The subnet he already gave you - even though he mistakenly called it an IP address. 145.36.0.0/22
Which class is it?
Classfull routing hasn't been used in 20+ years. So the question is mu. See RFC 1519/BCP 122. When people ask that question/talk about classes I politely remind them of that and ask them when the last time they touched a network was.
As for his answer (145.36.4.1 and 145.36.4.2). That is actually the next subnet (/22) up. So by definition his answer is incorrect. I am guessing that he is under the long mistaken belief that you cant use the zero subnet (which is totally incorrect - its just a set of bits so the zero subnet is 100% valid and used throughout the internet and has been for 30+ years).
If you send me his contact info I would be happy to send him an email to explain why he is wrong. My company name, my title and the letters and numbers after my name usually get peoples attention I want it to. ;)
You should have also asked him back if you could further subnet down the address space and assigned the interfaces out of a /31. When he said you can't use /31 you would know he is a moron and could call him out as such.
I don't tolerate people who believe themselves to be technically adept why spreading false information. I love crucifying those people - preferably in public or at least in a crowd of their peers.
DeusExMachina
01-06-2013, 09:09
True,,,and 145.36.4.0 would be the next available address range above 145.36.0.0/22
That's why I'm thinking its purposely confusing. "You have been assigned 145.36.0.0/22" "assign the next available host address on the next available subnet". That would lead to 145.36.4.1 and 2.
Thanks for the input everyone. It seems like at minimum I wasn't wrong with my answer based on the wording of the exercise and at most he may have even been wrong. So now the real question becomes... how to address this? As I've stated, I need to send a thank you email for the interview. I planned to CC all three of them in on it and also have individual notes for each person which they, of course, would all likely read. I thought that if I addressed this with him it would be the best way because it wouldn't come off as I'm a know-it-all and I'm just sharing a note with him which they happen to read as well. How to bring it up and how to word it?
Also, the pres asked me about Crystal Reports which I know nothing about. They were considering implementing it and waned my opinion. I wasn't going to BS them so I said that I had no personal experience with it to be able to take from. I quietly notated during the interview though and I want to be able to give him some more info as part of that email. Since being able to advise on new products moving forward is an attribute they stated they were looking for I think that a short but well thought out opinion in this same email would go a long ways. I think I've got the right audience in this thread for this portion as well so no sense starting a new thread for it. What do you know... good or bad.. that I may include to help make me look better as they make a decision?
So, who can help me with this bad boy?
cfortune
01-06-2013, 16:06
Don't know a thing about it.
Just looked it up on youtube and found a video of guy using it to pull data from a database. Looked like the advantage to it was being able to select predefined fields, making the end user not have to worry about column names, joins, etc. Not sure why a network engineer would need to be involved in this. Unless you were dumping syslog and or SNMP polls to DB and wanting to create reports on those.
We use Splunk for log consolidation which seems kind of similar. It indexes log files/SNMP/Syslog, almost anything that can be outputted. You can then quickly search through those logs, use regular expressions to create custom fields for your various log types, search for keywords or timestamps, create custom time ranges to dig through, etc. You can then create dashboards, alerts, and reports based off of the data that is returned from your searches.
Thanks for the input everyone. It seems like at minimum I wasn't wrong with my answer based on the wording of the exercise and at most he may have even been wrong. So now the real question becomes... how to address this? As I've stated, I need to send a thank you email for the interview. I planned to CC all three of them in on it and also have individual notes for each person which they, of course, would all likely read. I thought that if I addressed this with him it would be the best way because it wouldn't come off as I'm a know-it-all and I'm just sharing a note with him which they happen to read as well. How to bring it up and how to word it?
Also, the pres asked me about Crystal Reports which I know nothing about. They were considering implementing it and waned my opinion. I wasn't going to BS them so I said that I had no personal experience with it to be able to take from. I quietly notated during the interview though and I want to be able to give him some more info as part of that email. Since being able to advise on new products moving forward is an attribute they stated they were looking for I think that a short but well thought out opinion in this same email would go a long ways. I think I've got the right audience in this thread for this portion as well so no sense starting a new thread for it. What do you know... good or bad.. that I may include to help make me look better as they make a decision?
So, who can help me with this bad boy?
Crystal Reports in a popular Reporting/Business Intelligence tool. We use a more flexible, powerful suite of tools from Information Builders called WebFOCUS. WebFOCUS is used by MANY Fortune 100 companies, government agencies, etc., but also many mid-sized businesses as well. Go to www.ibi.com (http://www.ibi.com) to learn more.
Thanks for the input everyone. It seems like at minimum I wasn't wrong with my answer based on the wording of the exercise and at most he may have even been wrong. So now the real question becomes... how to address this? As I've stated, I need to send a thank you email for the interview. I planned to CC all three of them in on it and also have individual notes for each person which they, of course, would all likely read. I thought that if I addressed this with him it would be the best way because it wouldn't come off as I'm a know-it-all and I'm just sharing a note with him which they happen to read as well. How to bring it up and how to word it?
We would need to hear his explanation before we could give advice on how to handle it - that way you can hone in on exactly where his flaw in logic/wording was/is. Easiest thing is to blow it off and once you get hired confront him about it.
Also, the pres asked me about Crystal Reports which I know nothing about. They were considering implementing it and waned my opinion. I wasn't going to BS them so I said that I had no personal experience with it to be able to take from. I quietly notated during the interview though and I want to be able to give him some more info as part of that email. Since being able to advise on new products moving forward is an attribute they stated they were looking for I think that a short but well thought out opinion in this same email would go a long ways. I think I've got the right audience in this thread for this portion as well so no sense starting a new thread for it. What do you know... good or bad.. that I may include to help make me look better as they make a decision?
Best thing you can ever do in a technical interview is admit when you don't know something. I will hire a guy/gal who says they don't know but will research the question over anyone who tries to BS an answer. Technology is incredibly complex and utterly vast. It is impossible to know everything about everything. Its a full time second job just to know a little about a broad array of things.
As for an opinion on Crystal Reports - it doesnt do anything that you cant do with modern HTML/CSS/AJAX/RoR/etc and O/JDBC connections. It just makes it a little faster (to build) and cleaner (if your not a graphic artist with a background in GUI design) - but it locks you into their product. I am not a reporting monkey but I have spent enough time in databases to know enough to be dangerous. I would still in an interview say I knew nothing about the product.
I am guessing that he is under the long mistaken belief that you cant use the zero subnet (which is totally incorrect - its just a set of bits so the zero subnet is 100% valid and used throughout the internet and has been for 30+ years).
I'm leaning the same way, thinking that he may be confused.
As you pointed out there is no issue with using the zero subnet. Many people used to believe there were issues back when you had to add the "ip subnet-zero" command because it wouldn't work without it. If he's referencing E0 he could easily be talking about pre IOS 12.0 without the command.
"It should be noted that even though it was discouraged, the entire address space including subnet zero and the all-ones subnet have always been usable."
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080093f18.shtml#subne tzero
buckshotbarlow
01-06-2013, 17:36
you should of told the guy he's an idiot for doing it that way. 1 interface for an http server? wtf u thinking numb nuttz. HTTP should be on a dmz with a limited set of networks, class c with a /30 to limit the the amounts of attacks. Where's the fw infront of the http server to keep the kenyans, chinese and everybody else in sub sahara africa out???
Bumping this one up as it seemed like a pretty good audience of people in the biz. I haven't officially got the word yet but a little birdie told me that I may no longer be a candidate for this position. After 3 months and several trips to Nebraska I'm getting a bit tired of being kept in the dark on everything. Last I heard I was one of two candidates remaining and was going to be offered the job but still no word weeks later. I also have it on good authority that the position may have been offered to the other candidate and that's why I'm still in the dark. I guess they want a contingency plan in case he does't accept or something falls though.
In summary, I'm looking for a position and I posted a thread here (http://www.ar-15.co/threads/88891-Anyone-know-of-any-IT-positions-preferably-in-NoCO?p=940791#post940791) to try to get some help in finding work. If you guys can check that out and post leads or PM/email details I would be appreciative.
Thanks!
Network/Subnet Address = 145.36.0.0 which is a class B address AKA what you would use to advertise this network to neighboring routers (via OSPF for instance) and will appear as a directly connected network in this particular routers routing table
Assign E0 145.36.0.1 255.255.252.0, though at work I always use the last available IP of the subnet.
Assign HTTP server 145.36.0.2 255.255.252.0, with a gateway of 145.36.0.1
Why such a huge network range for such a small network is what I'd ask lol. 1022 useable addresses for a network containing one host is a bit absurd.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^DIS^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
We use Splunk for log consolidation
Splunk admin here!
Sitting at Splunk Live right now... Curious if any COAR members were splunking.
cfortune
08-13-2013, 09:48
Splunk admin here!
Sitting at Splunk Live right now... Curious if any COAR members were splunking.
I went to that a few years ago. They had some good grub for lunch.
Computer Science student here if that counts for anything
Computer Science student here if that counts for anything
Beats a business degree. You'll take my job one day.
I went to that a few years ago. They had some good grub for lunch.
Not bad at all... I think I'll be going to Splunk Conf in sept
Computer Science student here if that counts for anything
No. It doesnt. I have a guy on fiver who says he has a PhD in Computer Science from some prestigious university in Russia (or Egypt/Sudan/Israel/Syria/China/Korea) and will make me whatever hardware/software I want for $5 US..
Beats a business degree. You'll take my job one day.
And what job might that be?
No. It doesnt. I have a guy on fiver who says he has a PhD in Computer Science from some prestigious university in Russia (or Egypt/Sudan/Israel/Syria/China/Korea) and will make me whatever hardware/software I want for $5 US..
Well that sounds like a great deal. Im at UCCS right now and I cant beat that price!
ChadAmberg
08-14-2013, 08:39
Don't let him get you down. Remember, a computer guy based in the US is worth 5 overseas.
Because they'll hire 5 of them to replace you and you'll have to train them before you get to the unemployment line. And if you're the one still employed after the big outsource, when the overseas development team turns in their code, it won't work, it will be total crap, and it's easier for you to rewrite it all yourself just to get it done than make them fix it.
Just remember: Don't EVER apply for a development job where Java is used. Java is the language of "Your job is going overseas next month!"
cfortune
08-14-2013, 09:10
Don't let him get you down. Remember, a computer guy based in the US is worth 5 overseas.
Because they'll hire 5 of them to replace you and you'll have to train them before you get to the unemployment line. And if you're the one still employed after the big outsource, when the overseas development team turns in their code, it won't work, it will be total crap, and it's easier for you to rewrite it all yourself just to get it done than make them fix it.
Just remember: Don't EVER apply for a development job where Java is used. Java is the language of "Your job is going overseas next month!"
Our security guy has a printout pinned outside his cube. It's Java updating with the "3 billion devices run Java" marketing. Then directly below it, it shows him gaining root access to a machine via a Java exploit.
Powered by vBulletin® Version 4.2.3 Copyright © 2025 vBulletin Solutions, Inc. All rights reserved.