nix-config-ryan4yin/hosts/idols-aquamarine/README.md

Idols - Aquamarine

A router(IPv4 only) with a transparent proxy to bypass the G|F|W.

NOTE: dae(running on aquamarine) do not provides a http/socks5 proxy server, so a v2ray server is running on idols_kana to provides a http/socks5 proxy service.

Troubleshooting

Can not access the global internet

1. Check whether the subscription url is accessible.
   • If not, then you need to get a new subscription url and update the dae's configuration.
2. Check the dae service's log by journalctl -u dae -n 1000.

DNS cannot be resolved

1. sudo systemctl stop dae, then try to resolve the domain name again.
   • If it works, the problem is caused by dae service.
   • check dae's log by journalctl -u dae -n 1000
2. DNS & DHCP is provided by dnsmasq service, check the configuration of dnsmasq.

DHCP cannot be obtained

1. ss -tunlp, check if dnsmasq is running and listening on udp port 67.
2. journalctl -u dnsmasq -n 1000 to check the log of dnsmasq.
3. Request a new IP address by disconnect and reconnect one of your devices' wifi.
4. nix shell nixpkgs#dhcpdump and then sudo dhcpdump -i br-lan, check if the DHCP request is received by dnsmasq.
   1. The server listens on UDP port number 67, and the client listens on UDP port number 68.
   2. DHCP operations fall into four phases:
      1. Server discovery: The DHCP client broadcasts a DHCPDISCOVER message on the network subnet using the destination address 255.255.255.255 (limited broadcast) or the specific subnet broadcast address (directed broadcast).
      2. IP lease offer: When a DHCP server receives a DHCPDISCOVER message from a client, which is an IP address lease request, the DHCP server reserves an IP address for the client and makes a lease offer by sending a DHCPOFFER message to the client.
      3. IP lease request: In response to the DHCP offer, the client replies with a DHCPREQUEST message, broadcast to the server,[a] requesting the offered address.
      4. IP lease acknowledgement: When the DHCP server receives the DHCPREQUEST message from the client, it sends a DHCPACK packet to the client, which includes the lease duration and any other configuration information that the client might have requested.
   3. So if you see only DISCOVER messages, the dhsmasq is not working properly.

References

• https://github.com/ghostbuster91/blogposts/blob/main/router2023-part2/main.md
• https://github.com/ghostbuster91/nixos-router