**I n'ont pas changed *anything* related to le DNS entry for serverfault.com**, mais certains users were reporting today that [the serverfault.com DNS fails to resolve for them](https://meta.stackexchange.com/questions/7070/serverfault-down-how-to-get-into-superuser-beta/7079#7079).
I ran a [justping query](https://web.archive.org/web/20130216002155/http://just-ping.com/index.php) et I can sort of confirm this -- serverfault.com dns appears to be failing to resolve in a handful of countries, for no particular reason that I can discern. (also confirmed via [What's My DNS](http://www.whatsmydns.net/) qui does certains worldwide pings in a similaire fashion, so c'est confirmed as an issue by two différent sources.)
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Why would this be happening, si I n'ont pas touched le DNS for serverfault.com ?
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our registrar is (gag) GoDaddy, et I use par défaut DNS settings for le le plus part sans incident. Am I doing something wrong? Have le gods of DNS forsaken me?
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is there anything I can do to fix this? Any way to goose le DNS along, ou force le DNS to propagate correctly worldwide?
Update: as of Monday at 3:30 am PST, everything looks correct.. JustPing reports site is reachable depuis tous locations. Thank you for le beaucoup de très informative responses, I learned a lot et will refer to this Q le suivant time this happens..
Le DNS ne se propage pas dans le monde entier
Re: Le DNS ne se propage pas dans le monde entier
Ceci est pas directly a DNS problem, c'est a network routing problem entre certains parts of le internet et le DNS servers for serverfault.com. Since le nameservers ne peut pas be reached le domain stops resolving.
As far as I can tell le routing problem is on le (Global Crossing?) router avec IP address `204.245.39.50`.
As [shown](https://serverfault.com/questions/42678/dns-failing-to-propagate-worldwide/42686#42686) by [@radius](https://serverfault.com/users/9503/radius), packets to ns52 (as used by [stackoverflow.com](http://stackoverflow.com)) pass depuis here to `208.109.115.121` et depuis there work correctly. However packets to ns22 go à la place to `208.109.115.201`.
Since those two addresses are les deux in le même `/24` et le corresponding BGP announcement is aussi for a `/24` this *ne devrait pas happen*.
J'ai done traceroutes via mon network qui ultimately uses MFN Above.net à la place of Global Crossing to get to GoDaddy et il y a no sign of tout routing trickery ci-dessous le `/24` level - les deux name servers have identical traceroutes depuis here.
The seulement times J'ai ever seen something like this it was broken [Cisco Express Forwarding](http://en.wikipedia.org/wiki/Cisco_Express_Forwarding) (CEF). Ceci est a hardware level cache used to accelerate packet routing. Unfortunately juste occasionally it gets out of sync avec le real routing table, et tries to forward packets via le wrong interface. CEF entries can go down to le `/32` level even si le underlying routing table entry is for a `/24`. C'est tricky to find these sorts of problems, mais once identified they're normally easy to fix.
J'ai e-mailed GC et aussi tried to speak to them, mais they ne va pas créez un ticket for non-customers. If tout of you **are** a customer of GC, please try et report this...
**UPDATE at 10:38 UTC** As Jeff has noted le problem has now cleared. Traceroutes to les deux servers mentioned ci-dessus now go via le `208.109.115.121` suivant hop.
As far as I can tell le routing problem is on le (Global Crossing?) router avec IP address `204.245.39.50`.
As [shown](https://serverfault.com/questions/42678/dns-failing-to-propagate-worldwide/42686#42686) by [@radius](https://serverfault.com/users/9503/radius), packets to ns52 (as used by [stackoverflow.com](http://stackoverflow.com)) pass depuis here to `208.109.115.121` et depuis there work correctly. However packets to ns22 go à la place to `208.109.115.201`.
Since those two addresses are les deux in le même `/24` et le corresponding BGP announcement is aussi for a `/24` this *ne devrait pas happen*.
J'ai done traceroutes via mon network qui ultimately uses MFN Above.net à la place of Global Crossing to get to GoDaddy et il y a no sign of tout routing trickery ci-dessous le `/24` level - les deux name servers have identical traceroutes depuis here.
The seulement times J'ai ever seen something like this it was broken [Cisco Express Forwarding](http://en.wikipedia.org/wiki/Cisco_Express_Forwarding) (CEF). Ceci est a hardware level cache used to accelerate packet routing. Unfortunately juste occasionally it gets out of sync avec le real routing table, et tries to forward packets via le wrong interface. CEF entries can go down to le `/32` level even si le underlying routing table entry is for a `/24`. C'est tricky to find these sorts of problems, mais once identified they're normally easy to fix.
J'ai e-mailed GC et aussi tried to speak to them, mais they ne va pas créez un ticket for non-customers. If tout of you **are** a customer of GC, please try et report this...
**UPDATE at 10:38 UTC** As Jeff has noted le problem has now cleared. Traceroutes to les deux servers mentioned ci-dessus now go via le `208.109.115.121` suivant hop.