Intermittent Comcast DNS issues from VT
Since about midnight (Eastern) Comcast's DNS (75.75.75.7[5,6]) has been giving timeouts and the occasional 'no route to host' from Vermont. Switched our resolvers to use Google's Public DNS (via the same Comcast line) and all services returned to normal. Packet traces aren't interesting (just outbound traffic, no responses) and traceroutes to the cdn usually succeed. dns.comcast.net reports no problems. Queries at the command line sometimes succeed, sometimes fail, sometimes take a long time to finish. -Bill
Bill, I believe Comcast has anycasted their DNS servers, so if you could provide a traceroute to each IP then if Comcast personnel are lurking they can better guess which one it is. Frank From: Outages [mailto:outages-bounces@outages.org] On Behalf Of Bill McGonigle via Outages Sent: Friday, October 24, 2014 4:34 AM To: outages@outages.org Subject: [outages] Intermittent Comcast DNS issues from VT Since about midnight (Eastern) Comcast's DNS (75.75.75.7[5,6]) has been giving timeouts and the occasional 'no route to host' from Vermont. Switched our resolvers to use Google's Public DNS (via the same Comcast line) and all services returned to normal. Packet traces aren't interesting (just outbound traffic, no responses) and traceroutes to the cdn usually succeed. dns.comcast.net <http://dns.comcast.net> reports no problems. Queries at the command line sometimes succeed, sometimes fail, sometimes take a long time to finish. -Bill
Frank is correct. Bill, please send over a traceroute to 75.75.75.75 and 75.75.76.76 and I'll forward that information to the DNS infrastructure team. Thanks, John On Fri, Oct 24, 2014 at 6:04 AM, Frank Bulk via Outages <outages@outages.org
wrote:
Bill,
I believe Comcast has anycasted their DNS servers, so if you could provide a traceroute to each IP then if Comcast personnel are lurking they can better guess which one it is.
Frank
*From:* Outages [mailto:outages-bounces@outages.org] *On Behalf Of *Bill McGonigle via Outages *Sent:* Friday, October 24, 2014 4:34 AM *To:* outages@outages.org *Subject:* [outages] Intermittent Comcast DNS issues from VT
Since about midnight (Eastern) Comcast's DNS (75.75.75.7[5,6]) has been giving timeouts and the occasional 'no route to host' from Vermont. Switched our resolvers to use Google's Public DNS (via the same Comcast line) and all services returned to normal.
Packet traces aren't interesting (just outbound traffic, no responses) and traceroutes to the cdn usually succeed. dns.comcast.net reports no problems. Queries at the command line sometimes succeed, sometimes fail, sometimes take a long time to finish.
-Bill
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At home I have Comcast in Colchester, VT, I have systems monitoring a bunch of points from outside and inside including a RIPE ATLAS PROBE, using Comcast DNS listed below. None of my systems reported an drop or degradation of any service. Sorry, I do not have a mtr to provide. -Mike Michael T. Voity Network Engineer University of Vermont On 10/24/2014 8:48 AM, John Neiberger via Outages wrote:
Frank is correct. Bill, please send over a traceroute to 75.75.75.75 and 75.75.76.76 and I'll forward that information to the DNS infrastructure team.
Thanks, John
On Fri, Oct 24, 2014 at 6:04 AM, Frank Bulk via Outages <outages@outages.org <mailto:outages@outages.org>> wrote:
Bill,
I believe Comcast has anycasted their DNS servers, so if you could provide a traceroute to each IP then if Comcast personnel are lurking they can better guess which one it is.
Frank
*From:*Outages [mailto:outages-bounces@outages.org <mailto:outages-bounces@outages.org>] *On Behalf Of *Bill McGonigle via Outages *Sent:* Friday, October 24, 2014 4:34 AM *To:* outages@outages.org <mailto:outages@outages.org> *Subject:* [outages] Intermittent Comcast DNS issues from VT
Since about midnight (Eastern) Comcast's DNS (75.75.75.7[5,6]) has been giving timeouts and the occasional 'no route to host' from Vermont. Switched our resolvers to use Google's Public DNS (via the same Comcast line) and all services returned to normal.
Packet traces aren't interesting (just outbound traffic, no responses) and traceroutes to the cdn usually succeed. dns.comcast.net <http://dns.comcast.net> reports no problems. Queries at the command line sometimes succeed, sometimes fail, sometimes take a long time to finish.
-Bill
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John, A number of your anycast nodes for 75.75.75.75 and 75.75.76.76 appear to be rate limiting ICMP rather aggressively. I'd recommend cranking this up for purposes of troubleshooting. Best, -a On Fri, Oct 24, 2014 at 8:48 AM, John Neiberger via Outages <outages@outages.org> wrote:
Frank is correct. Bill, please send over a traceroute to 75.75.75.75 and 75.75.76.76 and I'll forward that information to the DNS infrastructure team.
Thanks, John
On Fri, Oct 24, 2014 at 6:04 AM, Frank Bulk via Outages <outages@outages.org> wrote:
Bill,
I believe Comcast has anycasted their DNS servers, so if you could provide a traceroute to each IP then if Comcast personnel are lurking they can better guess which one it is.
Frank
From: Outages [mailto:outages-bounces@outages.org] On Behalf Of Bill McGonigle via Outages Sent: Friday, October 24, 2014 4:34 AM To: outages@outages.org Subject: [outages] Intermittent Comcast DNS issues from VT
Since about midnight (Eastern) Comcast's DNS (75.75.75.7[5,6]) has been giving timeouts and the occasional 'no route to host' from Vermont. Switched our resolvers to use Google's Public DNS (via the same Comcast line) and all services returned to normal.
Packet traces aren't interesting (just outbound traffic, no responses) and traceroutes to the cdn usually succeed. dns.comcast.net reports no problems. Queries at the command line sometimes succeed, sometimes fail, sometimes take a long time to finish.
-Bill
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_______________________________________________ Outages mailing list Outages@outages.org https://puck.nether.net/mailman/listinfo/outages
participants (5)
-
Adam Rothschild -
Bill McGonigle -
Frank Bulk -
John Neiberger -
Michael T. Voity