A friend was having a connection problem between their home network and their cable ISP. His computers were working fine for a while after booting, but then within 24 hours, they would lose their networking capability. Turning off the router and then turning it back on, and rebooting the computers always solved the problem.
Notice that I said "computer(s)" — I recommend that you use a cable/dsl router even if you only have one computer!
There is at least one brand of routers that I do not recommend because the manufacturer sold them but never made any firmware updates available — they just put out a new model and expected us to buy it (not likely!). Linksys routinely makes firmware updates available on its products, including for older models.
I upgraded the router firmware and the problem stopped. If you have an intermittent connection to the Internet, check your router’s firmware version and then check the version at the manufacturer’s web site.
Look at the DHCP tab in the Router’s display (in your favorite browser) and check the setting on “Client Lease Time”, which is in minutes. I have this set at 0, which means one day. [hummmm, I think this was “no expiration” in the earlier version, but I may be mistaken]
I gave him a few other things to check or fix, while he was working on the problem:
- you HAVE changed the password for the router, haven’t you? Routers can be identified and attacked, and you don’t really want yours to be.
- on the Filters tab, I have all the radio buttons set to “Disable” except “Block WAN request” — you want to block here so that your router won’t respond and announce what it is. [Bill Machrome article in PC Magazine].
You probably have 4 "switched" Ethernet ports on the router. Try using a different port. Any other hubs or switches between the computers and the router? If so, try to bypass them for a while for testing.
Are either of these machines on a UPS, or are you at the mercy of a power blip? Since they both don’t happen at the same time, this isn’t likely to be the problem, but is something to think about. Depending on the power supplies you have in the computers, one may be more susceptible to low voltage or spikes than the other one.
Finally, his wife’s computer was having flaky loss-of-connection problems. It turned out that its MAC address was not being read consistently. (I could see her machine listed twice in the router’s dhcp clients table, with slightly differing MAC addresses).
I changed network cards in her machine and that solved the problem. Don’t recall what brand I put in, but it was likely Linksys or DLink — I pulled one of the $15-on-sale cards and put in another one.