So I had a no sync issue a couple of weeks ago. Tech came out, said the modem was bad (and it was a very old SMC one), and replaced it with one of the new Cisco DPC3825s.
Performance looks great, tests are good, streaming is good, torrents are good, FTP is good... Ping tests come back fine. Online gaming hasn't had any problems at all.
But any large RAR and EXE files I download off of websites (HTTP) get corrupted. RARs often give incomplete errors when extracting, and EXEs often get bad CRC failures.
This is pretty consistent with files over 400-500 megs, regardless of the source of the download. Are there any obvious things I can check? The modem is still set up default, however I have made this PC the DMZ (since it's for gaming.) Which makes it even more confusing because I thought DMZ would pretty much prevent anything from interfering with the connection to this computer.
The MTU is still set to default (0 = 1500 bytes.) It sure feels like an MTU issue to me, the first thing I checked, hoping it was set to some low number. Any ideas guys? It's driving me nuts!
Have you tried turning off the SPI(Stateful packet inspection) option on the router to see if that makes a difference? It can sometimes cause issues.
Here is a quick guide. Test without and report back.
Nope, that didn't work. Same problem with multiple files tested.
Any other suggestions, guys? I've tried both default MTU (0 which I guess is 1500 bytes) as well as 1492. Is there another setting I could try?
And scratch what I said earlier, it DOES affect FTP transfers too. It doesn't affect torrents because, of course, torrents can re-do corrupt packets or whatever as they process.
I will look in to a firmware update next, I guess. 😕
Tentatively, it appears that going to bridge mode and hooking up my old Netgear fixed this issue.
Though I sure would have preferred to find the "right" fix in the Cisco. Oh well.