RT-AC56U - Slow IPv6 speeds

I just upgraded to a RT-AC56U from a RT-N16 (I had been running Merlin on it until Merlin dropped support for it, then I was running Tomato Shibby/Advanced Tomato). After getting the AC56U set up on the latest Merlin FW as soon as I got it out of the box and configuring everything, I'm noticing that, while my download speeds on the Comcast speed test for IPv4 is coming in at my provisioned speed (I'm on Comcast), my IPv6 download speed is roughly half that, but upload speeds for IPv4 and IPv6 are fine.

Both download and upload speeds for both IPv4 and IPv6 were roughly the same and at my provisioned speed on the N16, down to the past few days before I swapped the routers (I had swapped out my SB6120 modem for a SB6141 about a week and a half ago and had been testing it a lot since); on the AC56U, I've gone and tweaked with the IPv6 firewall, NAT acceleration, DNS, and AiProtection settings and it's still the same: my IPv6 download speeds are taking a 50% hit vs. IPv4.

Anyone have any ideas?

Unless you have reason to use ipv6, disable it. IPv6 cause dns leaks. I have comcast as well and have no use for ipv6. Also Ipv6 in my experience cause dns slown downs when requesting internet pages. At least it was for me.

Use 0xFF as hex value

http://www.thewindowsclub.com/disable-ipv6-5-second-boot-delay

talon_262 said:

I had swapped out my SB6120 modem for a SB6141 about a week and a half ago and had been testing it a lot since

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Comcast might not have your modem provisioned correctly... check with their customer care team...

Rango said:

Unless you have reason to use ipv6, disable it. IPv6 cause dns leaks. I have comcast as well and have no use for ipv6. Also Ipv6 in my experience cause dns slown downs when requesting internet pages. At least it was for me.

Use 0xFF as hex value

http://www.thewindowsclub.com/disable-ipv6-5-second-boot-delay

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I'd just as soon not disable IPv6 if I don't have to, because that is the direction the Internet is going and more sites are coming online with IPv6 versions. As a matter of fact, I shouldn't have to disable IPv6, because IPv6 was working just fine, with no other changes, right before I swapped my N16 for the AC56U; it's an issue with the router, either in hardware or software, and that's what I'm trying to find out.

Just disabling IPv6 doesn't solve the problem, it's just a Band-Aid that pushes it off for another day.

sfx2000 said:

Comcast might not have your modem provisioned correctly... check with their customer care team...

Click to expand...

IPv6 was working absolutely fine on the SB6141 when my N16 was hooked to it; once I swapped the N16 for the AC56U a couple of days ago, that's when IPv6 download speeds went in the toilet.

talon_262 said:

I'd just as soon not disable IPv6 if I don't have to, because that is the direction the Internet is going and more sites are coming online with IPv6 versions. As a matter of fact, I shouldn't have to disable IPv6, because IPv6 was working just fine, with no other changes, right before I swapped my N16 for the AC56U; it's an issue with the router, either in hardware or software, and that's what I'm trying to find out.

Just disabling IPv6 doesn't solve the problem, it's just a Band-Aid that pushes it off for another day.

Click to expand...

Your call. IPv6 is garbage. YOU yourself just said ipv6 is slower then v4. I just told you ipv6 leaks dns and is slower with dns request. If you insist with v6 then don't complain about slower speed. I just told you it's problematic at best. If you insist then deal with it. Mine is disabled. Comcast also has nothing to do with ipv6. It is what it is at this moment. It might get way better year form now. Now i flush this down the toilet. Good luck !

FYi i run 6141 on 87u router. Ipv6 disabled gladly for security purpose and faster isp and dns speeds. No brainer for me. Give me a reason to enable it and i will ....lol

Rango said:

Your call. IPv6 is garbage. YOU yourself just said ipv6 is slower then v4. I just told you ipv6 leaks dns and is slower with dns request. If you insist with v6 then don't complain about slower speed. I just told you it's problematic at best. If you insist then deal with it. Mine is disabled. Comcast also has nothing to do with ipv6. It is what it is at this moment. It might get way better year form now. Now i flush this down the toilet. Good luck !

FYi i run 6141 on 87u router. Ipv6 disabled gladly for security purpose and faster isp and dns speeds. No brainer for me. Give me a reason to enable it and i will ....lol

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No, what I said was that IPv6 was slow on my new AC56U; IPv6 had been working perfectly fine before the router swap from a N16 a couple of days ago, so I suspected either a hardware or a software problem with the AC56U, which is what I was trying to find out here. As far as you having disabled IPv6 on your equipment, you can do what you want, because it's none of my business, but, as I said, I want IPv6 enabled and working properly.

Anyway, it's all a moot point, because I've solved my problem; I had done a factory reset on the stock router when I powered it up the first time, then flashed Merlin to it, but apparently forgot to do another factory reset after the Merlin flash. Nothing else gave me problems except the IPv6 issue; for shirts and giggles (and because I couldn't think of anything else to check), I did a factory reset tonight and, lo and behold, the IPv6 problem was fixed.



Nothing like a good ol' PEBKAC error to get one thinking; in any case, thank you anyway to all who replied to me.

Ipv6 is slower on my 66u and 87u routers. It causes dns leaks! Its suggested by ALL vpn providers to be diabled due to security leaks reasons.
If you want slower and less secure ip protocol it's all good, just don't blame speed on hardware. It is ipv6. Period.

Rango said:

Ipv6 is slower on my 66u and 87u routers. It causes dns leaks! Its suggested by ALL vpn providers to be diabled due to security leaks reasons.
If you want slower and less secure ip protocol it's all good, just don't blame speed on hardware. It is ipv6. Period.

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It's suggested by them to disable it only because it's not routed through their tunnel. IPv6 in itself is perfectly secure, and presents no security issue for anyone not using a VPN tunnel.

If anything, IPv6 is actually MORE secure than IPv4, since the standard includes various security-related specifications.

RMerlin said:

It's suggested by them to disable it only because it's not routed through their tunnel. IPv6 in itself is perfectly secure, and presents no security issue for anyone not using a VPN tunnel.

If anything, IPv6 is actually MORE secure than IPv4, since the standard includes various security-related specifications.

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Indeed, which is why I wanted IPv6 working properly on my AC56U; disabling it if you're not running all your network traffic through a VPN makes absolutely no sense to me, because IPv6 is has much more security built-in than IPv4.

BTW, Merlin, I hope you're doing well; I became a fan of your firmware quite a while back with my N16. I was bummed when you stopped development for it, but I knew I wanted to upgrade my router at least one more time before Google Fiber finishes building out in my city and starts signing people up sometime in the next year or so (using my router with their equipment may be tricky because of the way that each of their TV boxes in the home can be a WiFi access point, so I'm trying to figure out how to best modify my home network topology when that time comes). Looking at the specs of the newer Asus routers, I picked the AC56U, because it's compatible with your firmware, DD-WRT, and Tomato, so I have choices; I was able to pick up a practically brand-new AC56U off eBay for a song last week ($56 shipped USPS Priority Mail; it was listed used and the box had been opened, but everything was in the box [even the network cable] and factory-sealed).

That said, while I'm not a big fan of the AsusWRT GUI aesthetic (Advanced Tomato, which I wound up installing on my N16 a couple of months ago, is damn pretty and information-rich), the fact that you keep adding useful features and fixes to the stock firmware (many of which Asus merges into the main AsusWRT branch, which says a lot to me) and maintain stability is why, when I took the AC56U out of the box and powered it up for the first time, the first thing that I did was to put your firmware on it.

The RT-AC56U is often overlooked, but at its price, it's a very attractive product. Very few users actually have 3x3 (or 4x4) network clients, so it's a very reasonable alternative to the RT-AC68U. I've sold and configured a few for customers who needed either 802.11AC at a reasonable price or just a decent VPN server for remote access.

RMerlin said:

The RT-AC56U is often overlooked, but at its price, it's a very attractive product. Very few users actually have 3x3 (or 4x4) network clients, so it's a very reasonable alternative to the RT-AC68U. I've sold and configured a few for customers who needed either 802.11AC at a reasonable price or just a decent VPN server for remote access.

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My only quibble with the AC56U is that it's not wall-mountable, which kinda sucks, because I had constructed my network equipment space with having anything that was wall-mountable mounted (my SB6120 [now a SB6141] cable modem and my RT-N16). Since the AC56U isn't mountable, I had to move a couple of things around, but it seems to have worked out fairly well (it's sitting on top of my D-Link smart gigabit switch on my homemade wooden "rack"). I'll probably put that Dell monitor on a wall mount and put it where I had my N16 at, to at least get it away from the floor; I run Remote Desktop and/or TeamViewer on the PC (my media server, running Plex) and the Mac Mini (serving PlexConnect for the PC) there to access them remotely from my desk in the other room (or from anywhere else, for that matter), so that monitor only gets used when I can't remote in, such as to get into the PC BIOS or during major OS updates/upgrades.

I think I may have found what was causing IPv6 performance on my AC56U to plummet compared with IPv4, though I don't know why; playing with the AiProtection settings, I enabled "Malicious Sites Blocking" and "Infected Device Prevention and Blocking" and everything was still OK on the IPv6 front, but as soon as I enabled "Vulnerability Protection", IPv6 performance went in the toilet, just as it did in my OPs. However, when I turned "Vulnerability Protection" back off or restored my previous settings file, IPv6 was behaving correctly again; could it possibly be a bug?

BTW, I got my monitor in my network space mounted on the wall; I think it looks pretty good. Now, I just need to tidy up cables:

I'm seeing the same thing with my 68U. With aiprotection off my xfinity IPv6 speedtests are the same as my IPv4 at ~126 Mbps. When I enable Malicious Sites Blocking and Vulnerability Protection I get 1/2 the DL speed and 100 cpu core 1 usage. With just Malicious Sites Blocking I get 2/3 the DL speed and 100 cpu core 1 usage. With just Vulnerability Protection I get 1/2 the DL speed and 100 cpu core 1 usage. This is with NAT Acceleration set to Auto.

doczenith1 said:

I'm seeing the same thing with my 68U. With aiprotection off my xfinity IPv6 speedtests are the same as my IPv4 at ~126 Mbps. When I enable Malicious Sites Blocking and Vulnerability Protection I get 1/2 the DL speed and 100 cpu core 1 usage. With just Malicious Sites Blocking I get 2/3 the DL speed and 100 cpu core 1 usage. With just Vulnerability Protection I get 1/2 the DL speed and 100 cpu core 1 usage. This is with NAT Acceleration set to Auto.

Click to expand...

Same problem here regarding AiProtection, I have to leave all options disabled or I get greatly reduced IPv6 speeds on my AC68U. Another IPv6 speed problem I have encountered and posted about in the past involves QoS; sometimes when booting QoS would get activated before Comcast finished assigning me an IPv6 address and this also resulted in reduced Ipv6 speeds. I have not run into the problem recently, not sure if it is my new cable modem assigning me an address faster than before, or if there was some change to the firmware.

Rango said:

IPv6 is garbage... Give me a reason to enable it and i will ....lol

Click to expand...

http://ipv6.com/articles/general/Top-10-Features-that-make-IPv6-greater-than-IPv4.htm

Time to stop living in the 1990s, the IPv4 address pool has been exhausted and IPv6 is the only way forward.

I've been using IPv6 since 2012, and while it is usually slightly slower than IPv4, the difference is not noticeable. And I've never had DNS problems as a result of it. There have been times when IPv6 hasn't worked to some degree due to firmware problems, but when it is fully working it has never been a liability for me. Other people's experiences may differ, but that's what I've experienced.

On the other hand, my use of routers is pretty much as a router and for wireless, no DLNA or USB, no AiProtection or QoS, no VPN server, etc. So your experience may differ based on that, I don't know.

Hmm so I was testing this today on my 87U, and while I don't think SpeedTests are the greatest test, for me turning off all the AiProtection features does seem to help but only for LAN clients. For everything going over 5Ghz WiFi it makes no difference, in fact it's still faster than LAN even Weird.

I ran each test 2/3 times and they were pretty much the same every time.
IPv4 stayed about the same on all tests.

*EDIT: See 5Ghz results in next post. Can't post more than 3 images at a time.

All AiProtection On - LAN


All AiProtection Off - LAN

And the 5Ghz results:

All AiProtection On - 5Ghz


All AiProtection Off - 5Ghz

Huh I am seeing the same since upgrading an AC68 from an N66

N66 speeds from September last year



AC68 running latest version of Merlin

Turned off AiProtection Vulnerability Protection and got around 130-140 Mbps with IPv6.

Turning off the rest of AiProtection didn't seem to make a difference

Turning off QOS then got me back to 160 Mpbs



Edit I should also add turning off adaptive QOS moved buffer bloat from a B to D

2nd Edit - One more test a little better on speed and bufferbloat