Network Internal Loop

Fnlz

Hello Guys,

I hope someone can help me with my Problem.

A customer of us got a new connection with SIP-Trunking. Everything is working fine till we connect the Lancom to the Switch, like shown above. It is needed for the telephone system to communicate.

As soon as we connect it, the Internet goes down and enters some kind of loop.

Is it possible that the WAN Port in our Zyxel is missconfigured?

If yes, is there a sample-conf to setup the WAN Port for Ethernet?

Greetings.

mMontana

Can you change the Lancom 883+ subnet (and accordingly, USG115 Wan Port subnet)?

Try to use something different just like 192.168.250.0/24 subnet.

Long story short: use the same subnet on two different interfaces (not ports) AFAIK is not possible.

mMontana

Can you change the Lancom 883+ subnet (and accordingly, USG115 Wan Port subnet)?

Try to use something different just like 192.168.250.0/24 subnet.

Long story short: use the same subnet on two different interfaces (not ports) AFAIK is not possible.

Fnlz

https://businessforum.zyxel.com/discussion/comment/9797#Comment_9797

I will try it out, thanks :)

mMontana

any news to share, @Fnlz ?

Zyxel_Cooldia

Hi @Fnlz,

What is the Lan IP subnet of USG in this topology?

Fnlz

Sorry for the late answer.

@Zyxel_Cooldia

@mMontana 's solution did the job.

Thank you so much guys.

mMontana

Consider to split the switch into 2 vlans, for avoiding dual DHCP servers.

Fnlz

We already did 2 vlans, but for the guest wifi.

The DHCP server is disabled on the lancom, since normal clients obtain the IP through the Zyxel USG DHCP.

mMontana

Thanks for the explanation. Have a lot of fun.