Some websites limit an IP address's daily quota for downloading or
watching. To work around that, you may switch between a mobile network
and home WiFi for different public IP addresses. You may also toggle
Mobile Airplane mode on/off or reboot your home WiFi router after
waiting for a longer period. You can also use a VPN, but VPN IP
addresses are commonly shared by many users, so they may already be
blocked, flagged, or have reached the same limit. A VPN may also be
slower because traffic has to pass through the VPN server.
But you may have missed a hidden gem: your machine may already have a second rate-limit path for free, through a combination of a public IPv4 address and a public IPv6 address. By default, the browser or operating system may choose one of them behind the scenes based on availability, speed, routing, or other connection conditions.
At first, this may feel impossible because your public IP address sounds like something fully decided by the ISP, regardless of whether your local connection uses IPv4 or IPv6. That is partly true: you do not invent your own public IPv4 or IPv6 address. But on a dual-stack connection, the selected IPv4 or IPv6 path can determine which public IP identity the website sees. The small control you may have is choosing which existing path the browser uses.
Assuming you currently have IPv6, you may try to make Firefox use the website’s IPv4 A record, so the website sees your public IPv4 address instead of your IPv6 address:
about:config → network.dns.disableIPv6 → click false to change it to true → Ctrl + F5 to refresh the page.
Firefox is not telling the router to “force IPv4.” When Firefox uses a website’s A record, it has selected an IPv4 destination. The ISP may still tunnel or translate that traffic internally, but from the website’s point of view, the connection arrives as IPv4.
IPv6 cannot directly terminate on a publicly IPv4-only website under today’s standard internet protocols because IPv4 and IPv6 are separate protocol families with different packet formats, addressing, and routing systems. A hostname with only an A record is publicly IPv4-only: IPv6 clients have no IPv6 address to connect to for that hostname.
If an AAAA record is later added for an IPv6-capable CDN, reverse proxy, or load balancer, the public service becomes IPv6-capable, even if the origin server behind it remains IPv4-only. In that setup, the client connects to the front end over IPv6, and the front end separately connects to the origin over IPv4.
A mixed IPv6-source-to-IPv4-destination packet could theoretically exist, but it would be a new hybrid protocol that normal routers, firewalls, operating systems, and servers do not understand. In practice, crossing between IPv6 and IPv4 requires network-layer translation, such as NAT64 or 464XLAT, or tunneling/encapsulation, such as DS-Lite.Normal Firefox:
ask DNS for A + AAAA records of the target websiteIPv6 address exists and the browser/OS prefers the IPv6 connection
choose the website's IPv6 address: 2001:db8::10
connect from the client's IPv6 address: 2001:db8:1234:5678::abcd → rate limit hit
Firefox with network.dns.disableIPv6 = true:
do not use the IPv6 result
use the website's IPv4 A record: 203.0.113.10
connect from the client's public IPv4 address: 203.0.113.38 → fresh rate limit
A and AAAA commands to check the target website and what IP the target website sees from your machine:
echo "== DNS records of target ==" dig +short A example.com dig +short AAAA example.com echo "== Kernel route/source choice ==" ip -4 route get 203.0.113.10 ip -6 route get 2001:db8::10 echo "== Public IP seen by external service =="curl -4 https://ifconfig.mecurl -6https://ifconfig.me
Output:
== DNS records of target ==
203.0.113.10 # website IPv4 address
2001:db8::10 # website IPv6 address
== Kernel route/source choice ==
203.0.113.10 via 192.168.0.1 dev wlo1 src 192.168.0.15
# destination = website IPv4, source = local LAN IPv4
2001:db8::10 via fe80::1 dev wlo1 src 2001:db8:1234:5678::abcd
# destination = website IPv6, source = client IPv6
== Public IP seen by external service ==
203.0.113.38 # public IPv4 seen by website
2001:db8:1234:5678::abcd # public IPv6 seen by website*Although the curl test uses a different website from your target website, your public source IP usually stays the same for a given IP version on a direct connection: normal routing forwards packets toward the destination without rewriting the source address at each hop. The source IP changes mainly when something on your side or in the access path remaps it, such as NAT, CGNAT, a VPN, or a forward proxy. IPv6 privacy or temporary addresses can also rotate over time even without NAT or VPN. Separately, what the target website's internal server logs show may differ if the site is behind a CDN, load balancer, or reverse proxy: the public-facing edge may see the real client IP, while the origin server may only see the proxy's IP unless it restores the visitor IP from trusted forwarded headers such as X-Forwarded-For, X-Real-IP, or CF-Connecting-IP.
To check whether the target website may be behind a CDN or proxy, resolve the hostname and check who owns the returned IP address. A Cloudflare-owned IP usually means the site is Cloudflare-proxied, so origin logs may differ from what curl shows.
$ dig A example.com +short203.0.113.10203.0.113.11$ whois203.0.113.10| grep -i cloud NetName: CLOUDFLARENET ... RAbuseEmail: abuse@cloudflare.com RTechEmail: rir@cloudflare.com RNOCEmail: noc@cloudflare.com $
This
check is only a clue, not a perfect proof. If the DNS result belongs to
Cloudflare, that hostname is probably routed through Cloudflare's
proxy/CDN path. If the DNS result does not belong to Cloudflare, the
site may be direct-to-origin, or it may sit behind a different CDN, load
balancer, or reverse proxy provider. You can also check HTTP response
headers with curl -I https://example.com; headers such as server: cloudflare, cf-ray, or cf-cache-status are strong signs that the request actually passed through Cloudflare's edge.
For Cloudflare-proxied sites, the origin may see a Cloudflare/proxy IP unless it restores the real visitor IP from trusted headers. Rate-limiting by proxy IP is usually a weak setup because many visitors may share the same CDN/proxy address. A properly configured site should rate-limit by the real visitor IP from Cloudflare’s single-value CF-Connecting-IP or a correctly parsed X-Forwarded-For chain, but only when the request arrives through the expected trusted proxy path. In that case, the public IPv4/IPv6 shown by curl -4/-6 https://ifconfig.me is more relevant to the target site’s rate limit.
By combining mobile-network and home-WiFi IPs with both IPv4 and IPv6 paths, the rate limit is not just a second chance; in the best case, it can increase by up to 4x. If toggling airplane mode or rebooting the router successfully gives you a new public IP, the available quota may double again. Despite the public IPv4 address being shared by many users, Windows and browsers such as Chrome normally prefer IPv6 when it is working properly. Therefore, when you deliberately switch to IPv4, you may become one of the few users consuming the IPv4-based quota, making it less likely to have already been reached. Nevertheless, if the website supports only IPv4 or only IPv6, then the IPv4/IPv6 switching part of this trick will not work.
However, Firefox does not provide a matching network.dns.disableIPv4 setting for forcing IPv6-only browsing. The options are less direct:
1. Test with an IPv6-capable website and confirm the result with an IP-checking page.
2. Make sure network.dns.disableIPv6 is set to false.
3. Turn off Firefox DNS over HTTPS if it causes Firefox to behave differently from the system resolver.
4. Prefer IPv6 at the system level through /etc/gai.conf, although this affects more than Firefox and is not a Firefox-only switch.
5. For strict IPv6-only testing, use a separate network namespace, VM, VPN, or firewall rule to make IPv4 unavailable, then launch Firefox inside that environment.
Some websites may rate-limit by account session, cookie, or browser fingerprint, so changing from IPv6 to IPv4 may also need to be combined with a different account.
