@Criggn if it has never been enabled, I would try to enable it, some SIP systems require it to be enabled, others do not,

@Criggn Try and disable SIP ALG

@FarmTech to stop respond from gateway try create a gateway acl and deny gateway management. i have not tested this so at your own risk

@FarmTech Hello. when it comes to unifi and tp-link, they are quite similar. You want to block between vlans if I understand you correctly? this is done on the router as it is also done on unifi :-)...

@luke_ke1 Only v3 or newer ar supportet

@Bentie There is no wayt to disable any port on router. I use RJ45 Blanking Plug/ Dust Cap.. with a little glue its permanent disabled