if you are in an area where those hourly conquest updates are done, you could use those to narrow it down a bit.
- an idea why you might be dropping too though. Back a few years I worked part time with Comcast in the DC area. We did CMTS (basically the main brain units for the cable modems) reboots daily. They were rotated so all where never shut off at the same time and always had more than one up/down frequency for each channel going as well. 99% of the user base would never notice when maintenance was done because it never dropped your connection completely. Some games and VPN clients would notice it but only enough to kick them a second or less. I didn't play FFXI then, not sure if that hit it or not.
- Also our EAS (Emergency Alert System) would run a test at the exact same time to specific models of the new (at the time...) digital cable boxes. It's just a packet of info that tells the box to switch to the EAS channel for a real or test message. You know the "this is only a test. if this had been an actual emergency ..." message you get on the radio and TV sometimes? Same thing. Well, that pulse of information screws with some older cable modems floating around and drops them for a second. Usually a firmware update (if your manuf. has one) will fix it.
If you live in the DC area using Comcast cable, and your FFXI randomly drops every night at exactly the same time -- there's a pretty good guess why.
Lastly ... Comcast can kiss my *** -- one of the worst companies in the world to work for [i.e. "sorry ma'am, your computer is too old or defective" but I really know it's our shotty fiber nodes and rusty cable taps in your neighborhood that aren't on this years budget to replace and I just can't tell you because my nondisclosure statement said I wouldn't while employed with the company]) -- thank you.
***I just wasted most my internet time today on that paragraph haha ... damn 15 min time limits while deployed, oh well back to work.