Intrvw: Difference between revisions

2,489 bytes added ,  1 year ago
 
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Line 1:
= Google GCP Workspaces =
 
* Code:
 
<syntaxhighlight lang='python'>
with open('tab.txt','r') as tab, open('csv.txt','r') as csv, open('data.txt','w') as data:
for line in tab.readlines():
data.write(' '.join(line.strip().split('\t'))+'\n')
for line2 in csv.readlines():
data.write(' '.join(line2.strip().split(','))+'\n')
 
data.close()
 
 
with open('data.txt','r') as file:
for line in file.readlines():
print(line)
</syntaxhighlight>
 
* Code2:
 
<pre>
def analyze(numbers):
result = []
index = {}
min = None
max = None
for n in numbers:
index[n] = True
if not max or n > max:
max = n 9
if not min or n < min:
min = n 0
for n in range(min + 1, max):
if not n in index:
result.append(n)
return result
 
analyze()
 
 
4,5,6,7,8
3rd
0—-
 
 
analyze([5,9])
 
(6,9)
result = [6,7,8]
 
 
analyze([3,0,5,9])
4,3
 
 
Result = [1,2,4,6,7,8]
</pre>
 
* Equivalent Code:
<pre>
def analyze(numbers):
min = None
max = None
for n in numbers:
print(n)
if not max or n > max:
max = n
if not min or n < min:
min = n
print("max: ",max," min: ",min)
</pre>
 
* Results:
<pre>
>>> analyze([3,0,5,9])
3
max: 3 min: 3
0
max: 3 min: 0
5
max: 5 min: 5
9
max: 9 min: 5
</pre>
 
* Logic:
<pre>
>>> min = None
>>> not min
True
>>> min = 0
>>> not min
True
</pre>
 
* Working code for Min & Max:
<pre>
def analyze(numbers):
min = 0
max = 0
for n in numbers:
print(n)
if n > max:
max = n
if n < min:
min = n
print("max: ",max," min: ",min)
</pre>
 
= Amzn SysDE II =
 
Line 9 ⟶ 119:
 
* Coding
 
<pre>
<syntaxhighlight lang='python'>
## Write a function that gives you the average latency in a log file with the following format
#
Line 77 ⟶ 188:
 
avg_lat('/var/log/syslog')
</syntaxhighlight>
 
;Debrief
<pre>
feedback - team liked, pleasure in interview
strong NW
stron linux
LP fine
L4 is not good for you
System design not good
DB using indexing, Queues, scalable, parallel approach, LB using, indexing DBs, instead of storage.
Coding was also OK, difficulty with dictionary
Should know Datastructures not algorithms
Try again in 6 months, ask HR & try to get exception.
</pre>
 
* Correct Code:
<pre>
latency ={}
occurrance = {}
 
with open('latency2.logs','r') as file:
for line in file:
lat = int(line.split()[-1])
oper = line.split()[-2]
if oper in latency.keys():
add_latency = latency.get(oper) + lat
occurrance.update({oper:occurrance.get(oper)+1})
else:
add_latency = lat
occurrance.update({oper:1})
latency.update({oper:add_latency})
 
print(latency)
print(occurrance)
 
for k,v in latency.items():
print(k,int(v/occurrance.get(k)))
</pre>
 
Line 83 ⟶ 232:
* SSL Handshake
* TCP 3-Way Handshake
* TLS 1.0 vs TLS 3.0
 
* curl -kv (meaning of k)
* HTTP
 
= Microsoft =
Line 1,532 ⟶ 1,683:
= TechM (Chd) =
 
* SRX fxp1 interface
For SRX240B:
ge-0/0/0 interface will be mapped to fxp0 (out-of-band management)
ge-0/0/1 interface will be mapped to fxp1 (control).
The interfaces that are mapped to fxp0 and fxp1 are device specific.
* IPS blocked webmail. Where to get the alerts?
Analysis & Reporting > IPS > Intrusion Events
* Upgrade process of Sourcefire Sensors:
Reimage:
Reboot Sensor
Select System Restore
Set IP config
Select SCP, Enter Server IP, Credentials & ISO File name
Download & Mount ISO
Install
Reboot
* Screenos flow
* What is Sanity Checking?
* VPN
* NSRP Preempt behavior
* Proxy Server Experience
 
= ZScalar (Chd) =
 
DNS? need for DNS
Traffic troubleshooting
HTTP is in which layer?
DNS uses protocol? UDP & TCP
Why not use UDP for all DNS traffic? (Ans:Huge Overhead)
Reverse of DNS possible?
ScreenOS CPU utilization check command
Port no of DNS, SSH, HTTP
SSH access is there but WebUI not opening?
 
;2nd Level
 
302,403,401 error HTTP
SSL Handshake steps - 4 phases
Hashing vs Encryption, examples of protocols
Port Numbers - 80, 443
Proxy Server functions
ALG - Active vs Passive FTP
Destination NAT - Proxy ARP, Server issues, Debugging
If the Server does not have a reverse route to reach firewall,it will drop reply packet. Workaround is to create a Source NAT rule in firewall
Aggressive vs Main Mode
Is Preshared Key, ID shared in clear text in Aggressive mode? (no, its Hashed)
Dynamic IP in Site, Which mode is used? (Aggressive)
What is a Digital Signature?
 
 
= Convergys (JTAC L2) =
 
* VPN traffic is not reaching other gateway device? How to prove?
Ans:Take snoop simultaneusly at both sites.
 
* What filters to use for VPN Traffic?
Ans: 4 filters- two for & to the gateways, two to & for the PCs
 
* 4 VPNs between 2 devices, how to identify which packet is for which VPN?
Ans:SPI will be unique & remains same for a single VPN
 
* ESP has Port no?
 
* IMP:What is NAT-T? Why packet will drop without NAT-T? at which packet exchange will it drop?
Ans:At which packet level does it start using UDP port 4500?
 
*Scenario 1: