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New Visitor
SlowCast
Posts: 1
Registered: ‎08-11-2012

Change In DNS Servers

These guys really never cease to AMAZE me! They changed the DNS servers and did not tell anyone. This cost me lots of time and money as some people are not on auto detect settings and Comcast should know this!

 

You do not just change the DNS servers IP and NOT tell your customers! Un-Professional to say the least!

Gold Problem Solver
BruceW
Posts: 6,720
Registered: ‎12-03-2007

Re: Change In DNS Servers

What DNS change are you referring to?

Silver Problem Solver
andyross
Posts: 3,456
Registered: ‎10-17-2003

Re: Change In DNS Servers

?? Comcast moved to the DNSSEC servers at 75.75.75.75 and 75.75.76.76 a year or so ago! The old addresses just redirect to them. Before that, they were the default service for non-redirect users for awhile before that. Once they proved out OK, they were then moved over to all users. A GOOD side-effect is that ad-redirection is permanently disabled due to the way DNSSEC has to work.

 

The only issue with DNSSEC has primarily been with various .GOV sites that do not properly publish security key updates.

Official Employee
ComcastChrisG
Posts: 49
Registered: ‎10-17-2011

Re: Change In DNS Servers


SlowCast wrote:

These guys really never cease to AMAZE me! They changed the DNS servers and did not tell anyone. This cost me lots of time and money as some people are not on auto detect settings and Comcast should know this!

 

You do not just change the DNS servers IP and NOT tell your customers! Un-Professional to say the least!


The 75.75.75.75 and 75.75.76.76 addresses are handed out via DHCP. What IPs are you referring to? Also, if you would like to keep up to date on Comcast DNS news, please see http://dns.comcast.net.

 

Thanks,

Chris

New Visitor
LC-GoRAVENS
Posts: 1
Registered: ‎10-02-2012

Re: Change In DNS Servers

So the DNS change seemed to affect me starting yesterday morning... 75.75.75.75 / 75.75.76.76....

I have a server that does my DHCP, so I simply added a DNS forward so all my other computers on the network can get out. It was so strange how so many sites wouldn't come up.  I knew it was a DNS problem from the get-go and when I called support they denied it.

Networking Expert
kevj
Posts: 4,813
Registered: ‎10-03-2003

Re: Change In DNS Servers

But it was not Comcast's DNS problem, it was yours...how are Comcast supposed to know you run an internal DHCP server, and so advise you of their changes? A change in their DNS servers should be transparent to most users, but perhaps not for those that choose to deviate from the system that Comcast have implemented to (arguably) successfully support the majority of their subscribers. The vast majority of their subscribers obtain DNS information either directly through the Comcast DHCP servers, if their PCs are direct connected to a modem, or via their router, the majority of which run dnsmasq and are used by most subscribers as their default DNS server. The dnsmasq in the router handles forwarding of DNS traffic to the Comcast servers. You have chosen to hard code DNS servers into your personal DHCP server config, possibly without consideration of the consequences of an upstream change. If you are going to do that, it may be more adviseable to use well established DNS servers that are less likely to change IPs, such as Google or OpenDNS...

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Official Employee
ComcastChrisG
Posts: 49
Registered: ‎10-17-2011

Re: Change In DNS Servers

The DNS server IPs 75.75.75.75 and 75.75.76.76 are anycasted, so they will be around for a long time. I suggest referencing our DNS website at http://dns.comcast.net for more information.

 

Thanks,

Chris