[bitfolk] port 500 UDP

Hi there, I'm trying to troubleshoot an issue on my home network, using my Bitfolk VPN. I'm pretty sure the issue is with my ISP's network, but to be sure, is there any thing on Bitfolk's network that would be filtering incoming UDP packets to port 500? That's my question, but for the sake of clarity, this is the issue I'm actually trying to solve. I can't get WiFi calling to work on my home network. It used to work, but around the time I got a new router from the ISP (hyperoptic), it stopped working. I am pretty ignorant about how WiFi calling actually works, but it seems like it needs to send to UDP 500 to establish a tunnel into the telco network. I used netcat to try sending packets to my BitFolk host, and netcat on said bitfolk host to receive them. It seems I can send and recieve to port 499 and 501, but not port 500. My conclusion is that my ISP is somehow filtering out 500/UDP, but I need to know that it definitely isn't something at the bitfolk end, before I start wading through Hyperoptic's support tiers. I am aware that Hyperoptic use Carrier Grade NAT, but I pay extra for a static IPv4 so that *shouldn't* be an issue. Also, here's the Layer Four Traceroute for one of the EE WiFi calling gateways: sudo lft -z -u -d 500 109.249.190.48 Tracing ......********** TTL LFT trace to 109.249.190.48:500-516/udp 1 _gateway (192.168.0.1) 0.5ms 2 141.xxx.xxx.xxx.bcube.co.uk (141.xxx.xxx.xxx) 8.0ms # (redacted, my IP) 3 172.16.23.244 2.3ms 4 172.16.16.77 2.0ms 5 172.17.12.16 1.9ms 6 172.17.10.148 7.0ms ** [500-516/udp no reply from target] Use -VV to see packets. If anyone can assure me that it should be possible to recieve port 500 UDP packets at Bitfolk, that would be great, but happy to hear if anyone has any other insights into why WiFi Calling doesn't work for me, that would also be great. Thanks, -- Misha Gale PGP Public Key: 0x1986B8E1 https://mishagale.co.uk/pubkey.asc