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eg-253:networkq:654795 [2012/12/06 09:34] – [Question 11] eechriseg-253:networkq:654795 [2012/12/06 10:16] (current) – [Question 24] eechris
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   the program. You must have a gatewat interface access to run programs on your web page. It ensures higher security.   the program. You must have a gatewat interface access to run programs on your web page. It ensures higher security.
            
 +**No! In this context, the gateway is a //network layer// issue, it has nothing to do with application prootocols like the web and it is not explicitly concerned with network security.**
  
 +**Think about the Intenet Protocol and routing!** 
 +
 +**In fact all the configuration in ''/etc/hostname'', ''/etc/hosts'' and ''/etc/network/*'' is actually all about IP and Ethernet. It has nothing to do with the higher level protocols at all. The one exception is ''/etc/resolv.conf'' which is concerned with configuring your host to use DNS**
 +
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 03:35//
 ==== Question 14 ==== ==== Question 14 ====
  
 Which linux command shows the routing table for your host? Which linux command shows the routing table for your host?
  
-sudo route -n+  sudo route -n 
 + 
 +**Not sure that you need sudo. What does ''-n'' flag do?**
  
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:01//
  
-  Run the command identified in [[#question_14|Question 14]] and reproduce its output here.+Run the command identified in [[#question_14|Question 14]] and reproduce its output here.
  
   icct@tethys:~$ sudo route -n   icct@tethys:~$ sudo route -n
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   ip_forwarding = yes   ip_forwarding = yes
 +  
 +**The system feature is called //IP forwarding//. This is the command you use to turn it on!**
 +
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:02//
 ==== Question 17 ==== ==== Question 17 ====
  
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   icct@jupiter:~$ nano /etc/network/options   icct@jupiter:~$ nano /etc/network/options
  
 +**Because the question asks for the //file name//, a better answer would be ''jupiter:/etc/network/options'' -- but in actual fact, for your network the correct answer is ''saturn:/etc/network/options'', because the gateway router for your host is //saturn//!**
  
- +Reproduce the contents of the file defined in [[#question_17|Question 17]] to make a Ubuntu host into a router?
-  Reproduce the contents of the file defined in [[#question_17|Question 17]] to make a Ubuntu host into a router? +
- GNU nano 1.3.10          File: /etc/network/options                           +
  
   ip_forward=yes   ip_forward=yes
   spoofprotect=yes   spoofprotect=yes
   syncookies=no   syncookies=no
- 
- 
- 
- 
-                                [ Read 3 lines ] 
-  ^G Get Help  ^O WriteOut  ^R Read File ^Y Prev Page ^K Cut Text  ^C Cur Pos 
-  ^X Exit      ^J Justify   ^W Where Is  ^V Next Page ^U UnCut Txt ^T To Spell 
- 
- 
 ==== Question 19 ==== ==== Question 19 ====
  
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     up route add -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.1.4     up route add -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.1.4
 +
 +**What about ''down route''?**
 +
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:09//
  
   icct@jupiter:~$ cat /etc/network/interfaces   icct@jupiter:~$ cat /etc/network/interfaces
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   #auto eth2   #auto eth2
   #iface eth2 inet dhcp   #iface eth2 inet dhcp
 +
 +**Yes, except, you should have reproduced the file for saturn!**
 +
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:09//
  
  
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   IRTT: Initial Round Trip Time, the Kernel uses this to guess about the best TCP Protocol parameters without waiting on answers.   IRTT: Initial Round Trip Time, the Kernel uses this to guess about the best TCP Protocol parameters without waiting on answers.
   IFace: Interface to which packets of this route will be sent   IFace: Interface to which packets of this route will be sent
 +  
 +**Good idea to use the documentation for the definition, but what does it do in words that you and I could understand?**
 +
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:10//
 ==== Question 21 ==== ==== Question 21 ====
  
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   R: Interface is running   R: Interface is running
   U: Interface is up   U: Interface is up
 +  
 +**If anything, the official documentation of ''netstat -i'' is even more opaque. What does it really show us?**
 +
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:11//
 ==== Question 22 ==== ==== Question 22 ====
  
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   tcp        0      0 localhost.localdo:mysql *:*                     LISTEN        tcp        0      0 localhost.localdo:mysql *:*                     LISTEN     
  
-  The command -t displays all of the active TCP connections. A displays all active connections and the TCP and UDP ports on which the computer is listening.+  The command -t displays all of the active TCP connections. A displays all active connections and the TCP and UDP ports on which the computer is listening. 
   Combining them together gives the above output.   Combining them together gives the above output.
 +  
 +**Good, that's what I was after for the previous two questions! Perhaps the documentation is better for ''netstat -ta''**
 +
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:14//
 ===== Testing the Connectivity of your network ===== ===== Testing the Connectivity of your network =====
  
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   1  hyperion.saturn.icct.com (192.168.3.21)  0.753 ms  0.755 ms  0.748 ms   1  hyperion.saturn.icct.com (192.168.3.21)  0.753 ms  0.755 ms  0.748 ms
  
 +**The question asks you to provide a route to another network. You should have used something on jupiter.icct.com or icct.com. There would then have been at least 2 hops.**
  
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:12//
 ==== Question 24 ==== ==== Question 24 ====
  
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   29  * * *   29  * * *
   30  * * *   30  * * *
 +  
 +**How do you explain the no-reply status of hops 2-30? Do you think that there are there really 30 networks between hyperion.saturn.icct.com and www.swan.ac.uk?**
  
 + --- //[[chris@cpjobling.me|Chris Jobling]] 2012/12/06 04:15//
 ===== Extension Questions ===== ===== Extension Questions =====
  
eg-253/networkq/654795.1354786487.txt.gz · Last modified: 2012/12/06 09:34 by eechris