Recommended Posts

Hy guys!!
First question here and I'm a newbie  :)
During my Computer Networking exam, I was asked to find a simple rounting table both for the R4 router and the only host in this image
 
But, while the routing table for R4 is quite straightforward to me, the one for the host raised many doubts.
I tried something like that.
 
    IP dest              Mask                  Next Router          Out Interface
    194.17.21.0     255.255.255.0    //                            ??
     0.0.0.0             0.0.0.0               194.17.21.14          ??
 
Btw, I'm not sure if it's the right way to approach and what is the right Out interface.
Is it the same of the host IP (i.e. 194.17.21.16)? If yes, does it mean that the host out interface is the same of it's IP address? In other words, an host have the same IP address of its out interface? An host have the same IP address of its network device?
 
Thanks in advance :)
Link to comment
https://www.neowin.net/forum/topic/1197915-routing-table-for-an-host-ipv4/
Share on other sites

The host can see 2 routers, R4 and R5, it'd presumably route traffic through R4 due to the lower overall hops to get out to internet.

If it wants to send data to 192.16.7/24 it'd send data through R5, otherwise it'd send it through R4.

Edit: I think at least, haven't done routing since like 2011.

  • Like 1
  On 26/01/2014 at 11:17, The_Decryptor said:

The host can see 2 routers, R4 and R5, it'd presumably route traffic through R4 due to the lower overall hops to get out to internet.

If it wants to send data to 192.16.7/24 it'd send data through R5, otherwise it'd send it through R4.

Edit: I think at least, haven't done routing since like 2011.

Thanks for the support :)

Yes, I think you're right and I should modify the table.

Btw, what do you think about the output interface (and the related questions in the OP) ?

From the drawing the host only has 1 interface, so yeah that would be the out interface ;) Depending on the OS the route could be shown via the IP on the interface, or could be shown as the actual interface.

What OS is on the host would be the only way to be sure on the proper syntax of creating the route on the host.

So in that table can you see the routing tables of the routers shown? Is there any mention of routing protocol between them sharing their routes? If not its hard to say the proper route out. Which way does R2 route to network host is connected too, you would like to assume least hops - but you can not be sure without some more details.

If you were routing to the 192.16.7 network via r5, what would you be talking to in that network. A host, what routing table does it have? Because if it only has a default route out R3, you most likely run into a asynchronous routing problem with hosts talking to 192.16.7 from 194.17.21

As typical these sorts of questions/exams have little to do with a real life example.

Curious to see what the documented correct answer it - its always fun to ask how they got there with what is normally a lack of actual information given.

Then you have to love the just pulling networks out of their ass to use in diagrams, 111.0.0.0/10 owned by china mobile China Mobile Communications Corporation. APNIC, and then a Sweden TV network it seems RIPE..

Come on how hard is it to come up with a realistic diagram and question that reflects what might really happen in the realworld ;)

Lot of interesting stuffs here; don't know if I can be able to understand all of them tbh, but i get the points (I think :D ).
So, taking a (partial) real word example: suppose I have two network device, a wifi card and an ethernet card.
When I connect to the Internet via the ethernet card, my machine IP address is the same of the card?
What happens if I use both card to connect to the internet? Do I have two external IP address?

 

Thanks as always :)

Lets say you had wifi and wired -- Why would you connect to both at the same time would be my first question. Are they on the same network. For example my wireless is 192.168.2.0/24 while my wired would be 192.168.1.0/24

As to which one you would use to get to the internet - which one has the best metric?

Windows by default would use automatic metric to figure out which interface to use.. This metric is based upon a few different attribute of the connection. Speed being one of them - so wired would always be used you would have to assume over wireless if both have default gateways.

As to having 2 external address - external to where? More than likely your machine would be behind a nat to get to the internet anyway.. So even if you bounced off using wired for one connection and wireless for another connection to the internet you would still only have 1 address ;)

Multi homing a machine with more than 1 interface in the same network is normally not good practice and has its own issues btw.

So you saying wifi and wired at the same time is not really a valid real world example either - unless your talking some user at home that doesn't know any better and what to discuss why having this sort of connection could cause him issues ;) Then it would be a good real world example.. Look around the net you find lots and lots of FUD, where people suggest that user bridge his wired and wireless, or both of his wired intefaces for FASTER internet ;)

  • Like 1
This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Posts

    • That would be nice, if excel could refresh pivot tables without bugs. Frequently you refresh a pivot and all parameters get lost. Now this will happen automatically. Bravo MS!
    • If one could ever put all the crap of the world in one box, that would be Microsoft.
    • The most corrupt and vile CEO any company ever had ! The only company that makes an insane amount of money decade after decade but doesn't deliver on even barely passable quality to customers, screws over partners and treats employees like trash
    • PSA: Some other versions of Windows are losing support on October 14 too by Usama Jawad All of us here at Neowin likely know pretty well by now that Windows 10 is reaching end of support on October 14, 2025. You can extend support through paid and "free" means, but if you don't, you won't get any more security or feature updates following the aforementioned date. We also highlighted that the Long-Term Servicing Channel (LTSC) version Windows 10 22H2 is also reaching end of support on that date. Now, Microsoft has reminded customers that yet another variant of Windows is reaching end of life on October 14, 2025 too. On the Windows Release Health dashboard, Microsoft has published a reminder that the Enterprise, Education, and IoT SKUs of Windows 11, version 22H2 will hit end of support on October 14 as well. It is important to keep in mind that the Home and Pro variants of Windows 11, version 22H2 already reached end of life on October 8, 2024, and the extra year of lease on life will end for other SKUs within a few months too. Windows 11, version 22H2 for IoT, Enterprise, and Education was released on September 20, 2022, which means that they would have received just over three years of support by the time they "die", compared to the regular two years for Home and Pro. Customers on any of these versions should consider upgrading to version 23H2 or 24H2 as soon as possible, which have end of support dates of November 10, 2026 and October 12, 2027, respectively. Staying on a supported version of Windows is crucial as that allows you to receive regular security updates on your machine. If you're an IT admin, you should immediately begin planning a migration to a supported version of the operating system, and if you're an employee or someone using these versions of Windows in some other scenario, go to Settings > System > About and check out Windows Specifications > Version.
  • Recent Achievements

    • Week One Done
      hhgygy earned a badge
      Week One Done
    • One Month Later
      hhgygy earned a badge
      One Month Later
    • One Year In
      NIKI77 earned a badge
      One Year In
    • Week One Done
      artistro08 earned a badge
      Week One Done
    • Dedicated
      Balaji Kumar earned a badge
      Dedicated
  • Popular Contributors

    1. 1
      +primortal
      637
    2. 2
      ATLien_0
      239
    3. 3
      Xenon
      167
    4. 4
      neufuse
      146
    5. 5
      +FloatingFatMan
      123
  • Tell a friend

    Love Neowin? Tell a friend!