2 ISP routers 1 Switch

[zalves]

Hi!

I would like to connect two routers to my switch. They are both cheap routers that I can manage from my ISP, my switch is a Cisco SG350X-48P. One of the routers has the main internet line for all computers in the office, the other one has a secondary internet and where the voip telephones connect. Both routers have DHCP server on, so if I connect both to the router there is some sort of conflict.

Is it possible to have them run on different vlans? I tried programming the switch to have a few ports to be vlan2 and connect the second router, but I started to get some warning messages

Log Index Log Time Severity Description
2147481725 2019-Nov-25 17:55:05 Informational %AAA-I-CONNECT: New http connection for user cisco, source 192.168.1.66 destination 192.168.1.69 ACCEPTED
2147481726 2019-Nov-25 17:54:55 Warning %CDP-W-DUPLEX_MISMATCH: Duplex mismatch detected on interface gi2/0/1.
2147481727 2019-Nov-25 17:51:06 Informational %AAA-I-DISCONNECT: http connection for user cisco, source 192.168.1.66 destination 192.168.1.69 TERMINATED
2147481728 2019-Nov-25 17:49:55 Warning %CDP-W-DUPLEX_MISMATCH: Duplex mismatch detected on interface gi2/0/1.


anything I can do?

 

[coxhaus]

You should be able to do what you want. I am not excited about running internet traffic and LAN traffic in the same switch only protected by VLAN code.. It can be a security risk, just so you know it. Do not use the default VLAN or the management VLAN with internet traffic.

Duplex mismatch is auto port is not working for some reason for what ever device is plugged into gi2/0/1. You may need to manually assign duplex unless one of the devices is not on auto.

PS
You don't have to run dual ISPs to get priority for IP phones. You can code the SG350 for a voice VLAN and use one ISP which would be cheaper. Also this the normal way it is done. To me this is poor network design to run internet traffic across the same switch as LAN traffic.

I have decided the main internet line is not going through the switch but to the router first. So maybe you are only using the switch for LAN of 2 routers which is a much safer and better design than running internet traffic thought the Cisco switch also. The SG350 switches do not support dual default gateways so your design needs to work with that. I don't think that would be a problem with IP phones as they should point to your provider.

If I had to guess on your DHCP problem is you are mixing up layer 2 and layer3 as the SG350 switches run in both modes. On the old SG300 switch like I have they ran in layer 2 mode unless you put them in layer 3 mode. Also the SG350 switches only support 1 default route which I don't think you would need.

 

[Greg72]

A Switch or Router that is Dual WAN with failover capabilities is what is needed.