iMessage syncing slow?

Update: Although I couldn't figure out how to disable IPv6 on the router, I've just turned off IPv6 on my Mac side (needed to use the terminal to do so), and also forwarded the ports you mentioned to my specific Mac's internal IP via the xfinity router. Not sure which action is to credit, but they seem to have done the trick! Will update the thread if I've spoken too soon..

Humm,

Tell me more !!

Basically from an long time back we (regular posters who were dabbling with iChat at the time) found that Video and Audio only chats would tend to fail if the Mac was connected to the Internet by Ethernet and Wifi.

This effectively gives the Mac two IPs from the router.

AS data packets are addressed from the outgoing app via the router it uses, you get a very linear peer-to-peer connection to your Buddy.

Your Mac's IP on the LAN, to the Router's/Modem's IP from the ISP, (several inter-connecting servers), to Buddy's ISP and public IP, to the IP from the Buddy's router on the LAN.

The data packets contain the reverse address so that you get the packets back.

It gets confused if there are alternatives which is what happens when there are two connections.

Another issue that is similar is when you might piggy-back a neighbour's Wifi so that you are on two different network.

A further one is if one computer is connected to the router and another Share's it's internet connection. The usual way is for the first mac to be Ethernet to the router and share it's Connection via WiFi. In this case the second iChat could see the first mac's Internet Connection (it shouldn't) as well as it's own connection.

The presumption is that IPv6 has been coming for several years and it's uptake and deployment by ISPs has been very slow on the whole and very piecemeal. It is also not clear whether there is enough differentiation between the IPv4 connection and the IPv6 to allow Messages to ignore one.

Therefore this would lead to Messages seeing it as two connections if your ISP is doing it (Or the Buddies end if it was not before).

My pet theory was that some Internet backbone suppliers (the people beyond the ISP) had made massive changes somewhere. (Some companies involved are the same ones as some ISPs such as AT&T for example.

The Mac > System Preferences > Network offers the option of selecting "Local Link Only" in Yosemite for IPv6. There is not manual Off setting.

I would be interested to hear how you did this with Terminal.

7:40 p.m. Friday; July 24, 2015

I have wifi turned off on my iMac to prevent the very complications you refer to. I did notice the "Local Link Only" option in my preferences as well on Mavericks, but this website details how to turn it off via terminal.

Hi,

Thanks.

8:16 p.m. Friday; July 24, 2015

Sorry if someone's mentioned this already. This workaround is better than nothing for me:

In the morning I wake my mac (messages is already running). I wake the phone and click on the conversations that have unread texts in them. The messages show up on the Mac in a few seconds.

It occurs to me there are some variables I could play with, e.g., does Mac Messages have to be running when I click the iPhone messages? Does the Mac even have to be on or awake? Already got my morning messages so I can't test it.