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 Post subject: GNS3 - Ubuntu Cloud connetctivity issue
PostPosted: Fri Aug 24, 2012 10:25 pm 
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Joined: Fri Aug 24, 2012 10:16 pm
Posts: 3
Hi all

I have a problem that is driving me insane. Configured most basic network like this

R1 (fa0/0) 10.1.1.100 connects to Cloud (Ubuntu OS) 10.1.1.2

Ubuntu OS is running on ESXI5 as virtual machine

I am trying simple ping and telnet between 10.1.1.100 and 10.1.1.2 and intial problem was I could not get ARP on R1 for 10.1.1.100 and vice versa so I configured static ARP on both sides and now I cant get reponse.

I did TCPDUMP on Ubuntu while telnetting and pinging from GNS3 router and clearly request is coming in but nothing coming back as below

[email protected]:/home/wojtek# tcpdump -i eth1 host 10.1.1.2 -n
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth1, link-type EN10MB (Ethernet), capture size 65535 bytes
07:31:39.522638 IP 10.1.1.100 > 10.1.1.2: ICMP echo request, id 13, seq 0, length 80
07:31:41.521829 IP 10.1.1.100 > 10.1.1.2: ICMP echo request, id 13, seq 1, length 80
07:31:43.521640 IP 10.1.1.100 > 10.1.1.2: ICMP echo request, id 13, seq 2, length 80
07:31:45.520501 IP 10.1.1.100 > 10.1.1.2: ICMP echo request, id 13, seq 3, length 80
07:31:48.616603 IP 10.1.1.100 > 10.1.1.2: ICMP echo request, id 13, seq 4, length 80

07:31:57.037135 IP 10.1.1.100.58243 > 10.1.1.2.23: Flags [S], seq 2826649117, win 4128, options [mss 1460], length 0
07:31:59.033539 IP 10.1.1.100.58243 > 10.1.1.2.23: Flags [S], seq 2826649117, win 4128, options [mss 1460], length 0

So basically Ubuntu is not responsding to either TELNET (enabled) or ICMP

firewall is disabled as far as I know

any help appreciated




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 Post subject: Re: GNS3 - Ubuntu Cloud connetctivity issue
PostPosted: Sun Aug 26, 2012 9:34 pm 
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Joined: Fri Mar 05, 2010 11:33 am
Posts: 1494
Location: Australia
Pretty common problem. Have no idea why it doesn't work (although sometimes it might work for a while). Not sure about the ins & outs of ESX, but with VMWare Fusion I would do this:

Try adding a second adapter to your VM - a VMnet8 or VMnet1 (NAT or host-only - see http://rednectar.net/2011/07/20/vmware- ... -tutorial/ for more info)

Now connect your GNS3 Cloud to eth1 (the new VMnet1/8). If you give the router a DHCP address I think it will pick one up from the VMWare DHCP mechanism - if not you may have to play with IP addresses a bit to get your Guest OS and the Router on the same subnet.

Let us know how it goes.

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http://rednectar.net
@rednectarchris
GNS3 WorkBench-a VMware image of Ubuntu with GNS3 and VPCS installed and a collection of exercises/labs


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 Post subject: Re: GNS3 - Ubuntu Cloud connetctivity issue
PostPosted: Sun Aug 26, 2012 10:00 pm 
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Joined: Fri Aug 24, 2012 10:16 pm
Posts: 3
I don't have an option to add more NIC in vSphere and would rather understand why it does not work no matter how painful it is :)

just noticed that loopback might be taking part in it as for every ping I am getting counters incrementing on loopback0 which should not happen?


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 Post subject: Re: GNS3 - Ubuntu Cloud connetctivity issue
PostPosted: Tue Aug 28, 2012 11:53 am 
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Joined: Fri Aug 24, 2012 10:16 pm
Posts: 3
I managed to try adding new interface etc but still no luck.... I also created new Ubuntu VM inside Windows 7 and getting same results - no connectivity between GNS3 router and Ubuntu OS.

Looked a bit further and noticed all my connections are sent to loopback via Dynamips (i think)

21:00:12.241591 IP 127.0.0.1.43624 > 127.0.1.1.2004: Flags [.], ack 3397, win 2048, options [nop,nop,TS val 3418594 ecr 3418594], length 0
21:00:14.231000 IP 127.0.1.1.2004 > 127.0.0.1.43624: Flags [P.], seq 3397:3398, ack 164, win 2048, options [nop,nop,TS val 3419092 ecr 3418594], length 1
21:00:14.231050 IP 127.0.0.1.43624 > 127.0.1.1.2004: Flags [.], ack 3398, win 2048, options [nop,nop,TS val 3419092 ecr 3419092], length 0
21:00:16.235182 IP 127.0.1.1.2004 > 127.0.0.1.43624: Flags [P.], seq 3398:3441, ack 164, win 2048, options [nop,nop,TS val 3419593 ecr 3419092], length 43
21:00:16.235249 IP 127.0.0.1.43624 > 127.0.1.1.2004: Flags [.], ack 3441, win 2048, options [nop,nop,TS val 3419593 ecr 3419593], length 0

I can ping between UBUNTU VM and another VM like Cisco Call Manager so for me this is pointing to some GNS3 issue on Ubuntu?

Has anyone found any reliable solution for it?


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 Post subject: Re: GNS3 - Ubuntu Cloud connetctivity issue
PostPosted: Tue Aug 28, 2012 9:54 pm 
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Joined: Fri Mar 05, 2010 11:33 am
Posts: 1494
Location: Australia
1. I should have been more specific than "common problem" and quoted the FAQ rather than leading you on a wild goose chase. Sorry, I forgot that the faq says:
Quote:
On Linux / Unix / OS X, when I bridge a router or switch interface to my local host I can’t ping it from my host. But this works on Windows? What gives?

This does generally work on Windows (depending on your network card) but not on Linux / Unix. Most likely this is due to differences between libpcap and Winpcap, and the differences in the network stacks on Unix / Windows (e.g. NDIS). However you should be able to ping your bridged interfaces from other systems on the bridged network. If this does not work on Windows for your particular NIC, try creating a Windows loopback adapter and bridging to that. On Linux you can use a tap interface and the NIO_tap (available from a cloud). OS X you can install tun/tap drivers.


So the answer is to create a tunnel interface - you can bridge it to your eth1 interface if you want - see Josh Atterbry's article here or read this blindhog article.

2: Re
Quote:
Looked a bit further and noticed all my connections are sent to loopback via Dynamips (i think)

21:00:12.241591 IP 127.0.0.1.43624 > 127.0.1.1.2004: Flags [.], ack 3397, win 2048, options [nop,nop,TS val 3418594 ecr 3418594], length 0
21:00:14.231000 IP 127.0.1.1.2004 > 127.0.0.1.43624: Flags [P.], seq 3397:3398, ack 164, win 2048, options [nop,nop,TS val 3419092 ecr 3418594], length 1
21:00:14.231050 IP 127.0.0.1.43624 > 127.0.1.1.2004: Flags [.], ack 3398, win 2048, options [nop,nop,TS val 3419092 ecr 3419092], length 0
21:00:16.235182 IP 127.0.1.1.2004 > 127.0.0.1.43624: Flags [P.], seq 3398:3441, ack 164, win 2048, options [nop,nop,TS val 3419593 ecr 3419092], length 43
21:00:16.235249 IP 127.0.0.1.43624 > 127.0.1.1.2004: Flags [.], ack 3441, win 2048, options [nop,nop,TS val 3419593 ecr 3419593], length 0


This is just your console session. If you right-click on your router, select Change console port, you will see that the console port is 2004.

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RedNectar
http://rednectar.net
@rednectarchris
GNS3 WorkBench-a VMware image of Ubuntu with GNS3 and VPCS installed and a collection of exercises/labs


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 Post subject: Re: GNS3 - Ubuntu Cloud connetctivity issue
PostPosted: Sat Dec 28, 2013 11:34 am 
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Joined: Sat Dec 28, 2013 11:23 am
Posts: 1
create a tap interface and attach it in gns3 router instead of ethernet devices, the next step create a bridge attach tap interface and ethernet interface to that bridge now you will get your connectivity to gns3 router and ubuntu

and if you are trying send packets out from one ubuntu to other ubuntu which are on same esxi server through vswitch there you will face few problems, i faced one like i m able to get arp request and reply but for cmp traffic packets are getting dropped which are targeted to gns3 router,where my two ubuntu machines are able to communicate very well the only probllem is with gns3 router and ubuntu2 communication , the simple change you need to do is change the security parameter options in inventory>vswitch properties>ports change the security parameter as alllow on port-group which you are connecting two ubuntu machines


Regards,
Abhilash ramineni




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