Why Are IPv4 and IPv6 Ping Latencies Different? How to Test and Troubleshoot

When you run a Ping test against the same website, you'll often run into a situation that looks a little odd: IPv4 latency sits around 30ms, but switch to IPv6 and it jumps to 50ms, 80ms, or even higher. Some sites show the opposite—IPv6 Ping latency comes in lower than IPv4.

When people see this, their first instinct is often to ask, "Is IPv6 just slower?" In reality, that conclusion isn't quite right. For a website that supports both IPv4 and IPv6, the two protocols may reach the same domain name, but the DNS records, ISP routes, backbone networks, and CDN nodes behind them can all be different.

A latency gap between IPv4 and IPv6 Ping isn't unusual on its own. What really matters is figuring out: is this difference just normal routing variation, or has the IPv6 path started taking detours, dropping packets, or hitting ISP interconnection problems?

1. IPv4 Ping and IPv6 Ping aren't actually measuring the same network path

The core purpose of Ping is to measure the round-trip time (RTT) it takes for a packet to travel from the test host to the target and back. But IPv4 and IPv6 use two entirely different address systems and network paths.

When a domain provides service over IPv4, DNS typically returns an A record; when it provides service over IPv6, it returns an AAAA record.

For example:

A
203.0.113.10

AAAA
2001:db8::10

Even though you type the same domain name into your browser, these two addresses could easily point to different servers, different data centers, or even different CDN edge nodes.

Ping itself works differently too. IPv4 typically uses ICMP Echo Request and Echo Reply, while IPv6 uses ICMPv6. RFC 8200 establishes ICMPv6 as an essential part of any IPv6 implementation, and its specific protocol is defined in RFC 4443.

So when you see:

IPv4 Ping: 28ms
IPv6 Ping: 46ms

You can't simply read that as "IPv6 is 18ms slower than IPv4."

A more accurate way to put it:

When accessing this target from the current network, the IPv6 path has an RTT that is 18ms higher than the IPv4 path.

That shifts the focus of the problem entirely.

2. Why do IPv4 and IPv6 Ping latencies differ?

In practice, most IPv4 vs. IPv6 latency differences can be traced along the network path.

1. IPv4 and IPv6 take different ISP routes

This is the most common scenario.

Assuming neither your computer nor the target server has changed, IPv4 might go through:

User
 ↓
Local ISP
 ↓
Provincial backbone
 ↓
Target ISP
 ↓
Server

While IPv6 might go through:

User
 ↓
ISP IPv6 network
 ↓
IPv6 backbone
 ↓
Other interconnection nodes
 ↓
Target IPv6 network
 ↓
Server

The ASes, ISP exit points, backbone nodes, and interconnection links along the way can all differ. If one path takes a longer detour, the Ping latency will naturally differ.

So sometimes you'll see:

IPv4: 31ms
IPv6: 57ms

But test from a different region and it might flip to:

IPv4: 46ms
IPv6: 32ms

This isn't contradictory—it just means different test nodes have different IPv4 and IPv6 route quality.

2. A and AAAA records may be routed to different servers

There's another easily overlooked scenario: you think you're comparing the same server, but you're actually not.

Take a website behind a CDN, for example.

After DNS-based routing, the IPv4 A record might be assigned to a Shanghai node, while the IPv6 AAAA record—due to different node coverage or routing policies—gets assigned to a Beijing or even Hong Kong node.

The result could be:

IPv4
User → Shanghai CDN
Ping: 25ms

IPv6
User → Hong Kong CDN
Ping: 58ms

Even if the servers themselves are fine, IPv6 latency will still be noticeably higher.

So before comparing IPv4 and IPv6 latency, it's best to first check where the A and AAAA records actually resolve to, rather than just staring at two Ping numbers.

3. The same ISP's IPv4 and IPv6 network quality can differ

Just because a website supports IPv6 doesn't mean every region and every ISP will get the same network quality over IPv6 as they do over IPv4.

In some regions, IPv6 networks are already quite mature, with routes that are even more direct than IPv4. In others, there may be exit detours, mediocre ISP interconnection quality, or unstable regional routing.

Google's long-running IPv6 statistics also distinguish between "IPv6 availability" and reliability/latency issues that occur during connections. In other words, being able to use IPv6 and having a good IPv6 path are two different things.

This is also why testing from just your own computer once makes it hard to judge whether a website's IPv6 network is actually good or not.

4. IPv4 and IPv6 have different network forwarding environments

IPv4 addresses are a limited resource, so real-world networks often involve NAT, CGNAT, and similar devices. IPv6 uses a different addressing and forwarding architecture, so the network equipment and processing paths on each side can inherently differ.

But there's a common misconception here: you can't conclude that "IPv6 is always faster than IPv4" just because IPv6 eliminates some of the address translation steps in IPv4 networks. For actual Ping latency, what matters more is still physical distance, route selection, ISP interconnection, network congestion, and the location of the target node. An IPv6 route that goes through 15 hops and detours through another region won't automatically be faster than an 8-hop IPv4 route just because it's IPv6.

5. The IPv6 path may have detours or abnormal links

If you find that IPv6 is consistently much higher than IPv4, for example:

IPv4: 32ms
IPv6: 105ms

And the results are stable across repeated tests, it's worth digging into the routing.

Especially when the target servers on both sides are in similar locations, a fixed gap of tens or even hundreds of milliseconds often means IPv6 packets are traveling a longer network path.

At this point, repeatedly running Ping isn't very useful. You should start comparing IPv4 and IPv6 Traceroute results.

6. ICMP and ICMPv6 may be handled differently

There's another scenario that can easily lead to misjudgment: servers, firewalls, or intermediate network devices may apply different rate limits or priorities to ICMP versus ICMPv6.

For example:

IPv4 Ping: 30ms
IPv6 Ping: 75ms

This doesn't necessarily mean a webpage will load 45ms slower over IPv6 than over IPv4.

Ping tests observe ICMP round-trip behavior, but actually accessing an HTTPS website also involves TCP or QUIC connection setup, TLS handshake, HTTP requests, server processing, and content download.

Ping is great for finding network-layer issues, but it can't directly replace a website speed test.

3. How to test IPv4 and IPv6 Ping separately

If you just want a quick look at the latency from your current computer to a server, running Ping locally will do the job. But for a website, testing only from your own region isn't very representative. IPv4 and IPv6 route differences in particular often don't show up nationwide at once—they tend to concentrate in a specific region or a specific ISP.

In that case, testing from multiple nodes simultaneously is a better approach.

Just use Chahu's IPv6 website speed test, enter the domain or IPv6 address you want to check, and observe how the website performs over IPv6 from different regions and ISPs.

Currently, the test results show the responding IP, HTTP status, total time, DNS resolution time, connection time, and download time separately. You can also view performance across China Telecom, China Unicom, China Mobile, as well as Hong Kong/Macau/Taiwan and overseas nodes.

When testing, don't just look at a single "average speed"—what matters more is whether there are obvious differences between nodes.

For example:

If only Guangzhou Mobile's IPv6 is noticeably higher while other regions are close, you can't simply conclude that "this website's IPv6 is slow."

A more accurate conclusion would be: there may be routing, interconnection, or node scheduling differences between Guangzhou Mobile and the target IPv6 network.

One particularly useful feature of Chahu's IPv6 test is that you can directly see the final IPv6 address each node connects to. If the same domain resolves to different addresses in different regions, that means DNS or CDN scheduling itself may be contributing to the latency difference. The page also tracks the resolution ratio of different IPv6 addresses, making it easier to determine whether node scheduling is the culprit.

When testing, you can follow this approach:

Test IPv4 first
      ↓
Record latency across key regions
      ↓
Then test IPv6
      ↓
Compare the same regions and same ISPs
      ↓
Check whether only some nodes are noticeably slower
      ↓
Check the responding IP and resolution results

If IPv4 and IPv6 perform similarly across most nodes nationwide, that usually means the dual-stack routes are fine. If IPv6 is noticeably slower only on one ISP or in a few regions, you should dig into the local IPv6 routing. And if most IPv6 nodes nationwide are much higher than IPv4, then combining Traceroute, AAAA records, and CDN scheduling for further investigation will make it much easier to find the real problem than repeatedly running Ping on your own computer.

4. First confirm where the A and AAAA records actually resolve to

If the IPv4 and IPv6 test results show a significant gap, don't rush to judge which path has a problem. First confirm whether the two protocols are ultimately accessing the same region and the same set of servers.

Open Chahu's DNS lookup, enter the domain you want to check, and look at the A record and AAAA record separately.

Where:

• The A record corresponds to the website's IPv4 address;

• The AAAA record corresponds to the website's IPv6 address.

For example, after querying you might find:

A
→ IPv4 address
→ Shanghai node

AAAA
→ IPv6 address
→ Hong Kong node

In that case, even if the earlier test results were:

IPv4: 28ms
IPv6: 55ms

Nor should this be taken to mean that IPv6 network performance is inherently worse, because the two tests actually reached nodes in different regions. For a user in Shanghai, IPv4 was routed to Shanghai while IPv6 was routed to Hong Kong, and the two sides differ in physical distance and network path to begin with.

This situation is especially worth noting if the website uses a CDN. The A and AAAA records may go through different resolution and routing policies, ultimately landing on different edge nodes. Chahu's DNS lookup can also show resolution results from different regions, so beyond confirming "whether A and AAAA exist," you can also observe whether the addresses returned by different carriers are consistent.

The scenario truly worth investigating further is another one:

A
→ Shanghai IPv4 node

AAAA
→ Shanghai IPv6 node

The target regions on both sides are basically the same, but the test results are:

IPv4: 28ms
IPv6: 96ms

At this point, it becomes hard to explain it away simply by "the servers are in different locations."

If multiple test nodes can reproduce a similar phenomenon, it suggests that the IPv6 route itself may have detours, carrier interconnection issues, or differences in BGP routing. The next step should be to continue comparing the actual routing paths of IPv4 and IPv6 to see exactly where the latency starts to climb.

Therefore, what really needs to be confirmed at this step is not "whether the website has IPv6," but rather: where IPv4 and IPv6 ultimately resolve to, and whether the targets tested on both sides are comparable. Only after clarifying this point do the subsequent Ping and route comparisons become meaningful.

5. Using Traceroute to Find Out Exactly Where IPv4 and IPv6 Differ

If you confirm that the node locations corresponding to A and AAAA are roughly close, but there is still a clear difference in latency between IPv4 and IPv6, the next step is to continue comparing the two network paths. Compared with simply pinging repeatedly, Traceroute is better suited to determining exactly where the latency starts to climb.

tracert -4 example.com

And:

tracert -6 example.com

Suppose the IPv4 route is roughly:

Local
 ↓
Guangzhou Telecom
 ↓
Provincial backbone
 ↓
Hong Kong
 ↓
Target server

While IPv6 becomes:

Local
 ↓
Guangzhou IPv6 network
 ↓
Beijing
 ↓
Tokyo
 ↓
Hong Kong
 ↓
Target server

Then it is easy to explain why IPv6 Ping is several tens of milliseconds higher than IPv4.

This troubleshooting approach is more valuable than simply comparing average Ping, because it helps determine whether the problem occurs near the target server or has already appeared in the carrier's intermediate network. However, Traceroute also cannot be used mechanically to judge route quality by "how many hops" there are. Some intermediate devices do not respond to probe packets, and some backbone networks show fewer hops even though the actual physical path is not short. What you should really focus on is: from which hop the latency clearly climbs, and where IPv4 and IPv6 begin to diverge onto different routes.

6. How Much of a Difference Between IPv4 and IPv6 Ping Indicates a Problem?

There is no fixed answer to this question that applies to all networks. If IPv4 is 30ms and IPv6 is 36ms, a 6ms difference alone usually does not warrant overinterpretation.

Even if it becomes:

IPv4: 32ms
IPv6: 45ms

You still cannot judge IPv6 to be abnormal based on just those 13ms, because the two sides may go through different carrier exits or different CDN nodes.

What is truly worth paying attention to is "persistence" and "scope."

For example, a website consistently tests as follows over the long term:

A few milliseconds of difference occasionally does not matter; only long-term, stable, concentrated abnormalities are worth investigating further. If IPv6 not only has high Ping but is also accompanied by obvious packet loss, slow HTTP responses, or abnormal page loading, then the priority of the problem is even higher.

7. If IPv6 Ping Is Clearly Slower Than IPv4, in What Order Should You Troubleshoot?

When actually dealing with this kind of problem, I generally do not recommend directly modifying the server or disabling the AAAA record as soon as you see high IPv6 latency. It is more prudent to first pinpoint which layer the problem is at, and then decide how to handle it.

A more practical troubleshooting order is:

Discover IPv4 / IPv6 Ping difference
              ↓
        Query A / AAAA
              ↓
    Confirm whether target nodes are consistent
              ↓
   Test IPv4 / IPv6 Ping separately
              ↓
     Check packet loss and latency fluctuation
              ↓
Compare IPv4 / IPv6 Traceroute
              ↓
       Continue verification with multiple nodes
              ↓
 Determine whether it is concentrated in a region or carrier
              ↓
 Check CDN scheduling / BGP / IPv6 routing

If IPv6 tests are clearly higher across multiple carriers nationwide while IPv4 remains normal, the problem is more likely concentrated in the website server's IPv6 upstream, CDN IPv6 scheduling, or BGP routing. If only China Mobile's IPv6 is clearly higher while Telecom and Unicom are normal, then you should pay more attention to the interconnection path between the mobile network and the target IPv6 network. If abnormalities appear in only a few provinces, continue checking regional routing or the corresponding CDN nodes; there is no need to readjust the entire IPv6 network.

Another common situation is:

IPv4 Ping: 32ms
IPv6 Ping: 34ms

IPv4 website response: 120ms
IPv6 website response: 680ms

Ping is almost identical on both sides, but the IPv6 website's actual response is clearly slower. At this point, stop obsessing over Ping, because the underlying network RTT is already basically normal. The next step should focus on TCP, TLS, HTTP, server processing, or CDN origin fetch. Ping is better suited to observing the network link, while whether a website can be accessed normally also involves TCP, TLS, HTTP, and the web service itself.

Conclusion

A difference in IPv4 and IPv6 Ping latency does not mean that one protocol is inherently faster or slower. For a dual-stack website, the two sides may use different DNS records, carrier routes, backbone networks, and CDN nodes, so a certain RTT difference is normal.

In actual troubleshooting, first test IPv4 and IPv6 Ping separately, then check whether the A and AAAA resolutions point to similar targets. If the latency difference is fairly obvious, you can continue checking the path with Traceroute and confirm the scope of the problem using multi-node results from different regions and carriers. Only when you know where it is slow, which carrier is slow, and from which segment of the route it starts to slow down do IPv4 and IPv6 Ping data truly have diagnostic value. Comparing just two average latency numbers can easily lead to the wrong conclusion.

Related Q&A

Q1: Why is IPv6 Ping latency sometimes lower than IPv4? Is IPv6 really inherently faster than IPv4?

There is no law that "the IPv6 protocol itself must be faster." The core reason IPv6 Ping latency is lower is path optimization and hardware upgrades. On the one hand, many IPv6 network buildouts are newer, with better-performing router equipment, greater backplane bandwidth, and the elimination of the NAT/CGNAT address translation overhead common in traditional IPv4. On the other hand, some carriers or CDN providers have deployed more direct BGP backbone networks for IPv6, making the physical distance or transit nodes traversed by packets shorter than on detoured IPv4 routes.

Q2: Can disabling IPv6 on a local computer or server solve network lag or high Ping latency?

Directly disabling IPv6 is not recommended. Simply and crudely disabling IPv6 can avoid the occasional slow IPv6 node, but it also makes you lose pure IPv6 or IPv6-optimized acceleration paths. Modern operating systems (such as Windows, Linux, and macOS) generally implement the Happy Eyeballs (RFC 8305) mechanism. When a browser or application initiates access, it automatically initiates both IPv4 and IPv6 connections at the same time and prioritizes the path that actually establishes a connection fastest, so in the vast majority of cases manual disabling is unnecessary.

Q3: After enabling dual stack (IPv4 + IPv6) for a website, will it affect Google SEO rankings or search engine crawling?

Google has officially stated that IPv6 itself is not a direct SEO ranking signal. However, enabling correct dual-stack resolution can ensure efficient crawling by Googlebot in IPv6 environments and improve the actual loading speed and experience for some IPv6 users, thereby indirectly optimizing Core Web Vitals (CWV) data and positively helping the website's overall SEO stability.

Q4: How can multi-node testing determine whether it is a local carrier problem or a server origin problem?

Use Chahu's multi-node website speed test tool to observe IPv6 latency separately for Telecom, Unicom, Mobile, and different provinces. If only a specific region or specific carrier has clearly higher IPv6, it is a regional routing or cross-network interconnection bottleneck. If IPv6 latency is abnormally high across all nodes nationwide, it indicates that the server's upstream IPv6 route or BGP announcement has detours.