IPv4 vs IPv6 on Mobile Proxies: Why IP Checkers Show Both

You set up a mobile proxy, open an IP checker, and instead of a familiar address like 203.0.113.42 you see something long with colons in it. Nothing is broken: you are looking at your phone’s IPv6 address. This guide explains why it happens and how to keep what websites see consistent.

Two kinds of IP address

IPv4 addresses are four numbers, such as 198.51.100.17. There are only about four billion of them, far fewer than devices on the internet, which is why mobile carriers share each public IPv4 address between many subscribers through carrier-grade NAT.

IPv6 addresses are much longer, such as 2001:db8:4f2a::1c. There are so many that carriers can give every phone its own range. No sharing is needed.

Why phones have both

Carriers moved to IPv6 because they ran out of IPv4 addresses. Most now run dual-stack networks: each phone gets an IPv6 address and, alongside it, a private IPv4 address behind carrier-grade NAT. Some networks go further and are IPv6-only internally, translating to IPv4 at the edge.

When the phone connects to a website, the operating system chooses which protocol to use. If the site publishes both an IPv4 address (an A record) and an IPv6 address (an AAAA record), modern systems often prefer IPv6.

Why it matters for a proxy

The IPv6 address is genuine and belongs to the carrier. The problem is inconsistency:

• Sites reachable over IPv6 see one address; IPv4-only sites see another. To anyone comparing, you look like two different visitors.
• Your IPv6 address is unique to your phone rather than shared, so it carries less of the “crowd” protection that makes mobile IPv4 addresses so trusted.
• IP-reputation and location databases are often less precise for IPv6, which can show the wrong city.
• Allowlists and logs on your side usually expect one address per proxy.

How Proxynator handles it

When your client asks the proxy to open a connection, the app on the phone looks up the site’s addresses and tries IPv4 first. It falls back to IPv6 only if the site has no IPv4 address or the IPv4 connection fails. The result:

• sites that support IPv4, which is nearly all of them, see the carrier’s IPv4 address;
• IPv6-only sites still work;
• rotation changes both addresses, because the phone gets a new data session.

When you might still see IPv6

• Your client resolves DNS itself and connects to an IPv6 address. With SOCKS5, use socks5h:// so the proxy does the lookup and can choose IPv4. See HTTP vs SOCKS5.
• The site is IPv6-only. Rare, but then IPv6 is the only option.
• The traffic isn’t going through the proxy at all. If the address shown is your own network’s IPv6, the app or browser is bypassing the proxy settings.

Turning IPv6 off on the phone

Some phones let you set the APN protocol to IPv4 only under Settings > Mobile network > Access point names. Only do this if your carrier supports IPv4-only connections; on IPv6-only carrier networks it can break mobile data completely. With IPv4-first connections in the app, most people never need to change it.

Summary

Seeing an IPv6 address through a mobile proxy is normal on today’s dual-stack carrier networks. It is a real address, but mixing it with IPv4 makes your traffic look inconsistent. Connecting over IPv4 first keeps one address per phone in front of websites while IPv6-only sites keep working.

Frequently asked questions