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Switch not Sending out Broadcasts? GNS3 Emulation

ZoellerG
Level 1
Level 1

Hi Everyone,

i'm currently facing a really strange problem, i'm running a simulation in GNS3 with the following Topology

2023-10-17_16h30_10.png

The Switch to which everything is connecting (N301SWC01) is the coreswitch, the 2 other Switches that it's connecting to are the access switches (collapsed core),  this is where the strange things start happening, theres vlan 104 in which the access switches have an ip (10.1.104.xx/24), and every vlan is allowed on the trunk port, however both of the switches are not sending out arp broadcasts in the same vlan, basically every client thats requesting a arp reply, gets deadzoned, to ports to which the clients are connected are access ports in vlan 10. 

When i connect the pc3 to the core switch everything is working.

There are a couple of things i have configured on the access layer

  • ARP Inspection (validation of src-mac)
  • DHCP Snooping (database is lying on the ftp server)
  • ip source guard

Is there perhaps something im missing here?

If you need any running configs / Infos feel free to message here.

Greetings 

 

 

Georg György Zoeller
2 Accepted Solutions

Accepted Solutions

balaji.bandi
Hall of Fame
Hall of Fame

post below output from all the switches :

show run

show vlan

show ip interface brief

show ip route

show ip arp

 

BB

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View solution in original post

ZoellerG
Level 1
Level 1

Hi,

after a bit more testing i have found out that the problem is caused by ip source guard, apparently the source guard code in this version of iosvl2 is a bit buggy.

Thanks for trying to help!

Georg György Zoeller

View solution in original post

3 Replies 3

balaji.bandi
Hall of Fame
Hall of Fame

post below output from all the switches :

show run

show vlan

show ip interface brief

show ip route

show ip arp

 

BB

***** Rate All Helpful Responses *****

How to Ask The Cisco Community for Help

Hi,

Heres the Output

https://pastebin.com/kruPs27z - n301swa01711

https://pastebin.com/e1aAbjtZ - N301swa01511

i dont think i need the configuration of the coreswitch since arp seems to work properly on it, atleas my accesport in vlan 10 seems to be doing broadcasting the way it should.

 

all of the vlans are being learned via vtp

Thanks in advance.

Georg György Zoeller

ZoellerG
Level 1
Level 1

Hi,

after a bit more testing i have found out that the problem is caused by ip source guard, apparently the source guard code in this version of iosvl2 is a bit buggy.

Thanks for trying to help!

Georg György Zoeller
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