mDNSResponder trying to make connections to fwdr-12.fwdr-0.fwdr-252.fwdr-71

I use Little Snith to monitor my outgoing connections. Recently mDNSResponder has been making a connectionto fwdr-12.fwdr-0.fwdr-252.fwdr-71 (71.252.0.12.) When I do a "Whois" it comes back VCerizon Internet Services Co. When I look in my Network Systems Preference I see that this IP addess has been added as a secondary DNS server - the first being my router. So, why didn't Verizon just add the new DNS Server to my router?

Accepted answers

lasagna

That information is given to your client when you request a DHCP address from the router. It supplies your client with not only an IP address, but the DNS server addresses, and the default router information.

The router in the past has been providing "itself" as the only DNS server to the clients (192.168.1.1), but I suspect the firmware has recently started also supplying a secondary DNS server in case the DNS forwarding server inside the router were to happen to hang or otherwise fail. It's a very smart thing for them to do.

Since you mentioned mDNSResponder and System Preferences -- I'm going to assume that your using a Mac. One of things that changed when Apple went to Snow Leopard (actually, I think it was 10.6.2) is they "broke" the traditional DNS server "search order" code -- previously, it would start with the first server on the list and provided it responded, would never try any other server. Subsequent to Apple's update, the code now uses a combination of "fastest first" and "round robin" to locate a DNS resolver and as a result you may end up talking to any DNS server in the list of available servers. This has caused major havoc on split tunnel VPN configurations which were pushing down DNS server settings and inserting them at the beginning of the resolver list -- stuff that was work, now suddenly found itself randomly working or not working depending on how quickly particular DNS servers responded.

You can statically assign you own DNS servers -- although that is unwise -- or change your DHCP server settings on your router to have it provide alternate servers of your choice.

In short, what you are seeing is perfectly normal behavior.

All comments

dslr595148

@mustbjones wrote:
I use Little Snith to monitor my outgoing connections. Recently mDNSResponder has been making a connectionto fwdr-12.fwdr-0.fwdr-252.fwdr-71 (71.252.0.12.) When I do a "Whois" it comes back VCerizon Internet Services Co. When I look in my Network Systems Preference I see that this IP addess has been added as a secondary DNS server - the first being my router. So, why didn't Verizon just add the new DNS Server to my router?

I am just wondering.

Why would you want Verizon to do that for? It is your router, you are responsible for the state of your network.

mustbjones

Because this has nothing tyo do with my own network. The address, 72.252.0.12 is the same address that is in the software inside the router - look under network connections - Broaband Connection (coax) - and this is defualt factory settings (i.e. from Verizon.) So my question, and concern, is why has Verizon suddenly added this SAME address to my Systems Preference (because I sure and **** didn't!) If I was going to add another DNS server address it probably would be Google or OpenDNS.

lasagna

You can statically assign you own DNS servers -- although that is unwise -- or change your DHCP server settings on your router to have it provide alternate servers of your choice.

In short, what you are seeing is perfectly normal behavior.

mustbjones

Thank you. I won't try and block it with LittleSnitch.

nut4sports

My last name is Smith, but you can see that it is not in my email address. Also, I cannot (and certainly have not) see why or how you should have that problem. However, I have been having terrible problems with Verizon with my email and home network. I have reached a point where I have asked Verizon for a different router/modem. Several months ago, I even tried to run my Verizon through a Linksys router (which worked wonderful). I did not keep it like that because I was afraid Verizon would not help me if I had any problems with my bundle (TV, telephone, and internet). I wish the FiOS HD picture I receive was not so good. I have now requested a different type of router/modem from Verizon in hopes it will kill the problems.

Best of luck, I hope you have your problem corrected soon. Please let me know if I can help in any manner.

D. Smith

Richmond, VA