Internet drops throughout the day, both wired and wireless. Power cycling/resetting modem work, if/when the problem doesn't fix iself on its own (usually 10 minutes).
When it is down, the gateway can still be accessed, and status shows no problems. I've tried changing the DNS to OpenDNS & GoogleDNS, but problems continue to persist.
Please help.
Devices often report a "DNS Error" when they are actually having trouble reaching the Internet at all. This is because when you click a link or bookmark the first thing the device needs to do is look up the IP address of the site using DNS. Typically as the page loads this needs to be repeated many times to load all of the page components. If these lookups fail because of a connection problem the device won't be able to access DNS and may incorrectly announce a "DNS Error".
If you want to troubleshoot this yourself, please see Connection Troubleshooting Tips. If you still need help, please post your modem or gateway's signal information, especially downstream power levels and SNR, upstream power levels, and error log. There are usually found at http://10.0.0.1 or http://192.168.100.1.
Downstream bonded channels:
Channel | Lock Status | Modulation | Channel ID | Frequency | Power | SNR | Corrected | Uncorrectables |
1 | Locked | QAM256 | 4 | 417000000 Hz | -1.9 dBmV | 43.8 dB | 0 | 0 |
2 | Locked | QAM256 | 5 | 423000000 Hz | -2.0 dBmV | 43.7 dB | 0 | 0 |
3 | Locked | QAM256 | 6 | 429000000 Hz | -2.1 dBmV | 43.9 dB | 0 | 0 |
4 | Locked | QAM256 | 7 | 435000000 Hz | -2.1 dBmV | 43.8 dB | 0 | 0 |
5 | Locked | QAM256 | 8 | 441000000 Hz | -2.3 dBmV | 43.8 dB | 0 | 0 |
6 | Locked | QAM256 | 9 | 447000000 Hz | -2.6 dBmV | 43.6 dB | 0 | 0 |
7 | Locked | QAM256 | 10 | 453000000 Hz | -2.6 dBmV | 43.2 dB | 0 | 0 |
8 | Locked | QAM256 | 11 | 459000000 Hz | -2.6 dBmV | 43.2 dB | 0 |
0
|
Upstream channels:
Channel | Lock Status | US Channel Type | Channel ID | Symbol Rate | Frequency | Power |
1 | Locked | ATDMA | 2 | 5120 Ksym/sec | 30100000 Hz | 45.8 dBmV |
2 | Locked | ATDMA | 1 | 5120 Ksym/sec | 36500000 Hz | 45.5 dBmV |
3 | Locked | ATDMA | 3 | 5120 Ksym/sec | 23700000 Hz | 45.5 dBmV |
4 | Locked | ATDMA | 4 | 5120 Ksym/sec | 17300000 Hz | 45.8 dBmV |
Diagnostic log since 4/19:
Time | Priority | Description |
---|---|---|
Time Not Established | Notice (6) | Honoring MDD; IP provisioning mode = IPv6 |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Notice (6) | WiFi Interface [wl1] set to Channel 149 (Side-Band Channel:N/A) - Reason:INIT |
Time Not Established | Notice (6) | WiFi Interface [wl0] set to Channel 1 (Side-Band Channel:N/A) - Reason:INIT |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Fri May 29 14:16:41 2020 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Fri May 29 12:51:11 2020 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Fri May 29 05:56:34 2020 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Tue May 19 22:54:08 2020 | Critical (3) | Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.0;CM-VER=3.0; |
Time Not Established | Critical (3) | No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.0;CM-VER=3.0; |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Critical (3) | No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.0;CM-VER=3.0; |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Critical (3) | No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.0;CM-VER=3.0; |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Critical (3) | No Maintenance Broadcasts for Ranging opportunities received - T2 time-out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.0;CM-VER=3.0; |
Time Not Established | Critical (3) | No Ranging Response received - T3 time-out |
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
Time Not Established | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0; |
Sun Apr 19 23:52:10 2020 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Sun Apr 19 23:52:10 2020 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Sun Apr 19 23:51:41 2020 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Sun Apr 19 23:51:41 2020 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Sun Apr 19 23:51:07 2020 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Sun Apr 19 23:51:07 2020 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Sun Apr 19 23:50:48 2020 | Critical (3) | Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Sun Apr 19 23:50:47 2020 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
Sun Apr 19 23:48:22 2020 | Critical (3) | SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=74:ea:e8:f8:f4:c3;CMTS-MAC=00:01:5c:65:58:54;CM-QOS=1.1;CM-VER=3.0; |
@6910674 wrote: Downstream bonded channels: ... Upstream channels: ... Diagnostic log ...
The signals you posted look OK. The error log is difficult to interpret since the entries for date and time were not included. Suggest you continue to monitor the signal levels to see if they are "wandering" into out-of-spec territory.
If you can't find the problem call Comcast at the phone number on your bill or 1-800-Comcast, or use one of the options on https://www.xfinity.com/support/contact-us/. If they can't fix the problem remotely (unlikely), insist they send a tech out to identify the cause and correct it.
If the tech finds bad coax, splitters, amplifiers, or connections in your home (even if Comcast originally supplied them) you'll probably have to pay for the visit unless you have their Service Protection Plan (https://www.xfinity.com/support/articles/service-protection-plan, closed to customers that don't already have it). If the trouble is due to a faulty Comcast rental device, or anything outside your home, you shouldn't be charged.