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It appears that there is something blocking a large number of consumers from getting to www.webs.com. This seems to be caused by a blockage of dns queries ending with webs.com.

Can anyone duplicate this problem and determine where the blockage is originating?

For starters, run an nslookup (or dig) on www.webs.com. If that does not return an IP, then your nameservers are blocking webs.com. The question here is why?

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For the most part, nameservers don't "block" certain queries (except a few in the case of malware/badware sites, in which case they'll redirect to a warning page usually). This domain seems fine from every nameserver I have access to (several in the US and one in the UK). Post details of what your seeing and perhaps we'll be able to help diagnose. –  EEAA Feb 20 '11 at 19:37

3 Answers 3

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Have you done any DNS migrations the past couple of weeks?

I have tried resolving webs.com from various nameservers and only 1 set gives me SERVFAIL. The resolvers my ISP owns.

My own resolvers, Google DNS, Level3 DNS and direct lookups works out beautifully, just like they should.

I have seen this behavior before once. The problem seemed to be that the zones were migrated from one DNS setup to another, and that the new DNS setup used lower serials than the old one. It caused a lot of resolving nameservers to get really mad and refuse looking them up, even after changing the serials to being higher than the old ones.

I never actually got to know from the ISP that I contacted exactly what they did to their resolving DNS setup to get it working again.

Your current serial in SOA is "11434991" if you have migrated and your old provider used the typical YYYMMDDSS (SS being serial) then the new serial is in fact lower than the old one would have been.

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This is probably the closest to an answer. We never found the root cause, but it seems like at some point ISP's started getting invalid responses to lookups for our nameservers. This failed lookup got cached and couldn't be resolved without the isp's flushing their nameservers. We ended up switching our nameservers in our whois and that seemed to get things flowing properly again. –  Zeki Feb 23 '11 at 1:54

My new favorite DNS checking tool is DNSCog: http://www.dnscog.com/report/webs.com

I see a number of warnings and errors, but specifically it looks like ns2.webs.com is not responding with and IP, while ns1.webs.com is responding with an IP. This will cause random users to not be able to get to your web site.

I would also look into the other errors about SOA records and NS records missing.

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Your nameservers are both on the same AS, same subnet even. I'd try getting additional slave servers somewhere else first, via zoneedit for instance.

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A good suggestion, but not the root of the problem. –  Zeki Feb 20 '11 at 20:17
    
How do you know that? If the network where your nameservers are located at has availability problems from certain parts of the world, even if only intermittent, you'll probably experience a behaviour just like the one you described. –  al. Feb 21 '11 at 9:49
    
We are pretty certain this is a blockage. Other domains hosted on the same nameservers don't have the same problem. For example freewebs.com resolves everywhere, but webs.com is having problems. –  Zeki Feb 22 '11 at 0:55

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