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My Windows 7/64 machine has suddenly started to act funny. Everything will be running fine, when suddenly most network access methods will fail. These things continue to work:

  • Accessing network mapped drives
  • Ping (both intranet and internet)
  • DNS for URL resolution
  • Skype

These things fail:

  • Printing to a local network device
  • HTTP (I cannot browse to Internet sites, nor my local router's internal http server)
  • NNTP
  • IMAP
  • POP3
  • SMTP
  • Telnet

I've tried using ipconfig /release then /renew without success. Rebooting the machine cures the problem, until it happens again (anywhere from 4 to 40 hours later).

Any thoughts or suggestions?

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How exactly do these protocols fail? What errors do you get? What security software do you have installed? Do the problems persist if you (temporarily) disable or remove it? – Ansgar Wiechers Oct 7 '12 at 16:10
- When I say "fail", I mean that stop working, depending on how each reports errors. Browsers and Mail programs timeout, or immediately report an access error, printed documents stay parked in the spooler, etc. - I've had Norton 360 loaded for about 3 years on this machine. Although it does occasionally get overzealous, I've never had it do this before. I've not tried disabling it, as that would require uninstalling it. It's own logs haven't reported any problems. – Mike Hanson Oct 7 '12 at 16:13
To be more specific, this is related to TCP protocol since Ping is ICMP, DNS UDP and skype may use UDP only and still working afaik... – climenole Oct 7 '12 at 16:27
You say: «suddenly»... Check in devmgmt.msc for problematic network device (yellow triangle + err msg). Check also in eventvwr.msc for error or warning msg. If it's recent try a System Restore. – climenole Oct 7 '12 at 16:44
@climenole, thanks for that insight regarding the protocols. I'll definitely check those diagnostic tools. System Restore isn't an option, as it's been a couple of weeks since it first started happening, and many things changing on my machine on a regular basis. BTW, I can tell it's "suddenly", because I'll hear the message checking utility beep at me, and I'll discover that everything is wonky. – Mike Hanson Oct 7 '12 at 17:42

A few things to try:

  • Check for errors in the event viewer
  • Try restarting services manually. Rebooting will restart all services but there migth be this special service causing problems. Once you have identified it not only you will have a good clue but you would be able to solve you problem in seconds.
  • Check for someone chocking the network. Utorrent, Spotify, Grooveshark. I remmember having a similar problem with Spotify.
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