How do you get GNS3 to interact with "real" equipment?

earweedearweed Posts: 5,192Member ■■■■■■■■■□
I've heard about using GNS3 along with "real" switches for studying and didn't find anywhere how to do this.
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  • jahsouljahsoul Posts: 453Member
    earweed wrote: »
    I've heard about using GNS3 along with "real" switches for studying and didn't find anywhere how to do this.
    While I use dynamips so it's just configuring the virtual router interface to link with your real ethernet port in the .net file and then configure the port. I don't know if it works the same in GNS3.

    [FONT=&quot]Here is the tutorial site.

    Dynamips / Dynagen Tutorial
    [/FONT]
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  • chmorinchmorin Posts: 1,446Member ■■■■■□□□□□
    Tons of tutorials for this out in the interwebs, and it looks like some people threw out some links.

    In a nut shell:

    1) Toss down a cloud.
    2) Associate the cloud with your NIC.
    3) plug your NIC into your equipment.

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  • bermovickbermovick Posts: 1,132Member
    For the most part, it's just creating a loopback interface (if you don't already have one), and bridging the loopback and your actual network interface.
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  • thehourmanthehourman Posts: 723Member
    bermovick wrote: »
    For the most part, it's just creating a loopback interface (if you don't already have one), and bridging the loopback and your actual network interface.
    I am planning to do this as well.
    So far I have setup my SDM to connect to my 2621XM in GNS3.

    Ok, I only have one gigabit port on my PC, is it possible to connect all three switches and four routers to my GNS3 lab?
    Or do I need to get more NIC cards/usb?

    Thanks
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  • bermovickbermovick Posts: 1,132Member
    You shouldn't need more NICs; by bridging your Gigabit card, you're sortof making a virtual cable from whatever switch port hooks to your PC, through the PC bridge you made, into the 'cloud' you created in gns3, and into whatever you have the cloud connected to. Think of your PC as a 2-port switch/bridge, with the nic as 1 port and the loopback as the other.
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  • earweedearweed Posts: 5,192Member ■■■■■■■■■□
    bermovick wrote: »
    For the most part, it's just creating a loopback interface (if you don't already have one), and bridging the loopback and your actual network interface.
    Noob here, how exactly do you create a loopback interface,


    Also, If I stick an extra NIC (or 2) on my PC can I use these as interfaces for my real equipment? I'm looking to purchase hardware but since I'll have to buy a little at a time I'm gonna buy switches first and use GNS3 for the routers until I get real routers.
    No longer work in IT. Play around with stuff sometimes still and fix stuff for friends and relatives.
  • chmorinchmorin Posts: 1,446Member ■■■■■□□□□□
    earweed wrote: »
    Noob here, how exactly do you create a loopback interface,


    Also, If I stick an extra NIC (or 2) on my PC can I use these as interfaces for my real equipment? I'm looking to purchase hardware but since I'll have to buy a little at a time I'm gonna buy switches first and use GNS3 for the routers until I get real routers.


    You would only use a loopback if you want the virtualized equipment to be able to interface with your computer. You would point the cloud to the NIC on your computer to connect it to whatever the NIC is connected to.

    I'll probably end up making a GNS3 tutorial sometime in the future. I'll let you know.
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    mikej412 wrote:
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  • earweedearweed Posts: 5,192Member ■■■■■■■■■□
    Thanks, I'm linking this and a few other threads and sites to my "taking the CCENT/CCNA thread to keep them together and to minimize the bookmarks I have on my computer.
    No longer work in IT. Play around with stuff sometimes still and fix stuff for friends and relatives.
  • earweedearweed Posts: 5,192Member ■■■■■■■■■□
    I got offered free use of a Boson simulator for my CCNA studies. Anyone here use(d) it and your opinion of it.
    Upside
    Downside
    Howare the simulations and how does it compare to the real thing (hardware)
    No longer work in IT. Play around with stuff sometimes still and fix stuff for friends and relatives.
  • chmorinchmorin Posts: 1,446Member ■■■■■□□□□□
    earweed wrote: »
    Howare the simulations and how does it compare to the real thing (hardware)

    While I can't speak from boson, I'll tell you real world experience working with the equipment is much more valuable than any lab. However, a lab to me has always been a lab. Meaning it does not matter how you drill the studies, but as long as you actually are drilling them.
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    mikej412 wrote:
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  • bermovickbermovick Posts: 1,132Member
    chmorin wrote: »
    You would only use a loopback if you want the virtualized equipment to be able to interface with your computer. You would point the cloud to the NIC on your computer to connect it to whatever the NIC is connected to.

    I'll probably end up making a GNS3 tutorial sometime in the future. I'll let you know.

    This is pretty important; a GNS3 topology doesn't need to interface with your computer or physical equipment; you can 'console' into one of the routers and ping / traceroute / whatever to verify connectivity to the other side of the virtual network without needing any of it to see your default gateway or anything.
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  • mikej412mikej412 Posts: 10,090Member
    earweed wrote: »
    your opinion of it.
    Upside
    Downside
    Boson is probably the best and most complete simulator out there.

    Upside: It's enough to get you past the CCNA exam. The included labs work with the simulator and help teach you the things you need to know and should be able to demonstrate hands on for the CCNA exam.

    Downside: Cost -- you can build a real hardware lab for the same price. If you go outside the included labs you may hit a software bug. If you want to go beyond the CCNA basics (and the included labs) the simulator may not support the commands or work as expected (like the real hardware).

    Hopefully it's gotten better since the last time I looked at it. If they offered the CCNP version (and CCNA/CCNP labs) for the cost of the CCNA version (and kept making it better) then it might be worth it just for the convenience of being able to lab anywhere you can go with your laptop.
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  • NetwurkNetwurk Posts: 1,155Member
    mikej412 wrote: »
    If you want to go beyond the CCNA basics (and the included labs) the simulator may not support the commands or work as expected (like the real hardware)

    Good point by Mike here. One thing I've seen from folks who have used Boson is that the short form of commands is different than the real thing. For instance, I saw a guy complaining in a thread (not on this site) that the command span portfast would not work for him on the test no matter how many times he entered it. Problem was that he was trained on Boson and on some platforms span is also short for SPAN commands which are used by the Switched Port Analyzer (SPAN) feature. So if he had entered spann portfast he would have been fine.

    The guy complained that he ran out of time due to how long it took for him to answer the portfast question and that all his other short form commands worked. But of course the Cisco tests emulate real equipment, not Boson sims.

    The nice thing about GNS3 is that it uses the real Cisco IOS. It's not perfect, but it is way better than Boson.

    I use GNS3 to save me from tearing down my existing lab to experiment on a router lab exercise. It's cool to know how to connect it to your physical lab, but I don't do it as it would only further complicate my lab configs. One less thing to troubleshoot.

    ;)
  • thehourmanthehourman Posts: 723Member
    Netwurk wrote: »
    Good point by Mike here. One thing I've seen from folks who have used Boson is that the short form of commands is different than the real thing. For instance, I saw a guy complaining in a thread (not on this site) that the command span portfast would not work for him on the test no matter how many times he entered it. Problem was that he was trained on Boson and on some platforms span is also short for SPAN commands which are used by the Switched Port Analyzer (SPAN) feature. So if he had entered spann portfast he would have been fine.

    The guy complained that he ran out of time due to how long it took for him to answer the portfast question and that all his other short form commands worked. But of course the Cisco tests emulate real equipment, not Boson sims.

    The nice thing about GNS3 is that it uses the real Cisco IOS. It's not perfect, but it is way better than Boson.

    I use GNS3 to save me from tearing down my existing lab to experiment on a router lab exercise. It's cool to know how to connect it to your physical lab, but I don't do it as it would only further complicate my lab configs. One less thing to troubleshoot.

    ;)
    Question for you.
    What OS do you use? (Windows, Mac, Linux)

    I have it on Linux and never gotten a problem, other than I can't use SDM and no loopback interface, so no cloud.

    Therefore, I installed GNS3 on my Win7. Then all the stuff that I can't get from Linux I can run them under Win7; however, I can't keep my putty consoles open. They keep closing for no reason, and when I try to open them they close right away.
    The CPU processes is about 15% with 5 routers and 2 clouds (internet and SDM).

    Any idea man, why the console terminal can't stay open?
    Studying:
    Working on CCNA: Security. Start date: 12.28.10
    Microsoft 70-640 - on hold (This is not taking me anywhere. I started this in October, and it is December now, I am still on page 221. WTH!)
    Reading:
    Network Warrior - Currently at Part II
    Reading IPv6 Essentials 2nd Edition - on hold
  • earweedearweed Posts: 5,192Member ■■■■■■■■■□
    Netwurk wrote: »
    The nice thing about GNS3 is that it uses the real Cisco IOS. It's not perfect, but it is way better than Boson.

    I use GNS3 to save me from tearing down my existing lab to experiment on a router lab exercise. It's cool to know how to connect it to your physical lab, but I don't do it as it would only further complicate my lab configs. One less thing to troubleshoot.

    ;)
    i plan on using Boson until I get some swtches. I'm kind of limited spending the money for a lab at one time so I'm trying to find how you basically interface the GNS3 simulator with real switches. I have 2 spare NICs and everything on my computer if that'll help. I'm planning to buy a couple switches first but haven't decided which ones yet, the opinions here on the boards are really mixed about which switches are best for the CCNA lab.
    The Boson will stay on the laptop so I'll have a convenient lab wherever I'm at.
    No longer work in IT. Play around with stuff sometimes still and fix stuff for friends and relatives.
  • bermovickbermovick Posts: 1,132Member
    You should already have a loopback under linux:
    lo Link encap:Local Loopback
    inet addr:127.0.0.1 Mask:255.0.0.0
    inet6 addr: ::1/128 Scope:Host
    UP LOOPBACK RUNNING MTU:16436 Metric:1
    RX packets:112360 errors:0 dropped:0 overruns:0 frame:0
    TX packets:112360 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:0
    RX bytes:125397239 (119.5 MiB) TX bytes:125397239 (119.5 MiB)

    The tricky part is making a bridge. I looked this up and found a script you can run before starting gns3:

    ... which apparently I've lost.. dangit.

    Actually (and I think this is a no no, but I'd already done all the work of writing up how to get gns3 working (with a cloud) under linux, as well as getting sdm working as well, and I'm too lazy to just re-write it all.

    Linux + GNS3 + SDM?
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  • mikej412mikej412 Posts: 10,090Member
    You can either add a bunch of real NICs (supported multiport or USB) to a PC (or multiple PCs and distribute your virtual routers over several PC).

    Or you can use the simulated switch and VLANs that's available within Dynamips/Dynagen and use your PC's NIC to trunk out to a real switch -- and you the use the corresponding switchport on that switch to attach to your real hardware as if it were the real Ethernet port on the emulated routers.

    http://www.techexams.net/forums/ccie/40234-new-idea-unknown-if-working.html#post293219
    :mike: Cisco Certifications -- Collect the Entire Set!
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