Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

My wifi connection (from my MacBook running Snow Leopard) to a Time Warrner cabel model and router has a recurring connection problem. Every 20 minutes or so it will enter a "dead state" where no data can be transfered and yet pings still work:

$ ping
PING ( 56 data bytes
64 bytes from icmp_seq=0 ttl=245 time=13.029 ms
64 bytes from icmp_seq=1 ttl=245 time=16.214 ms
64 bytes from icmp_seq=2 ttl=245 time=16.221 ms
64 bytes from icmp_seq=3 ttl=245 time=15.778 ms
64 bytes from icmp_seq=4 ttl=245 time=16.220 ms
--- ping statistics ---
5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 13.029/15.492/16.221/1.243 ms

$ telnet 80

Notice the successfull pings to but trying to make an HTTP GET on port 80 hangs. A few minutes later:

$ telnet 80
Connected to
Escape character is '^]'.

HTTP/1.0 200
Content-Type: text/html
Content-Length: 349
Connection: close
Date: Tue, 07 Jun 2011 11:38:21 GMT
Server: lighttpd

In the dead state I don't get:

Connected to 
Escape character is '^]'.

Any idea what the problem is and how to fix? I can power cycle the modem and turn wifi on/off and it eventually comes back. But it comes back from a dead state after just waiting a few minutes too. My goal is to get a solid 24/7 connection that never has these dead periods. This has nothing to do with BTW, all sites have the same problem during the dead period.

More info from router logs:

Mon Jun 06 09:12:22 2011     
Error (4)    DHCP RENEW sent - Invalid DHCP option 

Fri Jun 03 14:51:21 2011     Critical (3)    Started Unicast Maintenance Ranging - No Response received - T3 time-out 

Time Not Established     Critical (3)    DHCP FAILED - Requested Info not supported. 

Wed Jun 01 12:36:00 2011     Critical (3)    DCC aborted unable to communicate on new upstream channel 

Wed Jun 01 12:36:00 2011     Critical (3)    Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 timeout 
share|improve this question
First, it would be helpful to know the exact model of the modem. Second, have you tried this with a second computer to isolate if it is your computer or the modem? Right now, it is very hard to even guess where to point you. – KCotreau Jun 7 '11 at 12:04
Does it do this for wireless and ethernet connections? – Moab Jun 7 '11 at 13:21
@Moab: DHCP servers are not something that can be changed. You either get an IP address from them or you don't. DNS servers wouldn't make a difference; he can still ping the outside world, but can't hit websites. – Kevin M Jun 7 '11 at 14:34
oops, used the wrong term. – Moab Jun 7 '11 at 14:53
Change your DNS servers in the router or each PC, I use OpenDNS servers myself. and – Moab Jun 7 '11 at 14:54

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.