DNS & network news

Monthly Archive: November 2016

451 4.4.0 dns query failed on exchange 2010 For all domains

HELP PLEASE. im getting the 451 4.4.0 dns query failed for every domain. We can not send any outbound emails out. they are all sitting in the queue.

The company got a ransom ware virus, and in the process of correcting everything they restarted the Exchange server, thats when they noticed that they could not send emails to external addresses.

I feel like it has to be something simple im missing that will start sending everything once fixed. something with resetting the DNS? I know i have limited information to go off of. what other information is needed?

submitted by /u/JD_85
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gTLD Recommendations & Theory

Because of recent flakiness in certain ccTLD authoritative nameservers, I need to create a reference document recommending that gTLDs such as com, net, org, and info be preferred to those with potentially flaky infrastructure. Can anyone point me to some documentation I might use as background research in creating this? In particular, I’m looking for information regarding the increased reliability of gTLDs, not how the DNS system works, how registrars work, and so on.

Yes, it’s mainly the .io debacle that’s prompting action.

submitted by /u/libcrypto
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What do DNS service providers do, exactly? (help a n00b)

Forgive my lack of knowledge, I’m completely new to this. I’m learning about various protocols and the general architecture of the Internet. I’m doing a project on the October 21 DDoS attack on Dyn Inc., which shut down a good chunk of the US’ Internet. I’m pretty sure I get the whole “DNS is like the Internet’s phone directory,” that we need a way to convert human language URLs into IP addresses in order to route, and all that. But what exactly is a DNS service provider? I thought DNS was more of a public utility. Can anyone explain to me how exactly Dyn, a private company, figures into the infrastructure of the Internet and why a DDoS attack on their servers effectively blocked access?

submitted by /u/OneLinerMiner
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Issue with resolving MX records

Hello everyone This morning (danish time) we saw an issue with resolving MX records on all our Office 365 costumers. I do not think it was an issue with Office 365 but rather a DNS issue. We did not manage to figure out what went wrong before the problem was gone. See this post from another sub: https://www.reddit.com/r/sysadmin/comments/5aonkw/office_365_issues_in_emea/?st=iv0ocpee&sh=c6dfbc10

This is exactly what we experienced. Did anyone else manage to figure out what the problem was?

submitted by /u/aies4president
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