Question

IP Forwarding trouble - hosts can't go to internet

  • 12 February 2021
  • 2 replies
  • 44 views

Hi,

i tried to configure a extreme switch with two vlans:

vlan500- ISP - 10.0.0.20/29

vlan3572 - local users - 10.83.72.1/24

My default route to this communication is ISP (10.0.0.17). 

I can ping the 8.8.8.8 with source 10.0.0.20 (ISP) that i can see request/reply on my firewall logs but when i try with source 10.83.72.1 looks link the traffic move to internet but not answer back. And when i try with a notebook on vlan 3572 untagged on port 2:40 i can’t ping 8.8.8.8 and no logs on my firewall.

A friend told me that if i configure ip fowarding will solve my problem.

Anyone can tell me if this is right?

Regards,

Rodrigo


2 replies

Hi Tomasz,

thanks for your help and answer your questions.

First, the next-hop knows how to reach 10.83.72.0/24 because the switch has an ip with the same network from and i have the same configuration on another site but with a switch Huawei.

Next week i try this configuration and send back a message here.

Thanks again

Rodrigo

Userlevel 6
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Hi Rodrigo,

 

What switch family do you mean, is it ExtremeXOS software? If so, ‘enable ip forwarding’ is responsible for making your switch working on L3 like a router. Then, if it gets 8.8.8.8 echo request from vlan 3572, it will lookup its route table and forward to the next-hop. But, does the next-hop router know how to reach back to 10.83.72.0/24?

These are two things I’d double check for troubleshooting this. Please let us know if any of those worked for you.

 

Hope that helps,

Tomasz

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