dns

Can I determine if a given “hostname” is a CNAME via Perl

由 十年热恋 提交于 2019-12-10 16:30:18
问题 At work I have something like this... $ host www.something.com www.something.com is an alias for some.other.address some.other.address is an alias for one.more.address one.more.address has address xxx.xxx.xxx.xxx I would like a way, in Perl to put in www.something.com and determine if it's a CNAME, A record, etc. 回答1: use Net::DNS qw(); my $query = Net::DNS::Resolver->new->search('conferences.yapceurope.org'); if ($query) { foreach my $rr ($query->answer) { next unless 'CNAME' eq $rr->type;

Nodemailer getaddrinfo ENOTFOUND Error

由 假如想象 提交于 2019-12-10 16:28:16
问题 Looking for some insight into this error I'm getting. on smtpTransport.sendmail(func(err, info){}) The err variable returns this: Error: getaddrinfo ENOTFOUND smtp.gmail.com smtp.gmail.com:465 at errnoException (dns.js:50:10) at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:92:26) and my code is: var smtpTransport = nodemailer.createTransport({ service: 'Gmail', auth: { user: 'xxx@gmail.com', pass: 'xxx' } }); var mailOptions = { to: user.email, from: 'xxx@gmail.com', subject: 'Node.js

Linux服务之高速缓存DNS

由 霸气de小男生 提交于 2019-12-10 16:19:34
DNS总览 1 . 权威名称服务器 存储并提供某区域（整个DNS域或DNS域的一部分）的实际数据。 2 . 权威名称服务器的类型包括： Master ：包含原始区域数据，有时称作主要名称服务器； Slave ：备份服务器，通过区域传送从Master服务器获得区域数据的副本，有时称作次要名称服务器。 3 . 非权威/递归名称服务器 客户端通过其查找来自权威名称服务器的数据。 递归名称服务器的类型包括仅缓存名称服务器：仅用于查找，对于非重要数据之外的任何内容都不具有权威性。 什么是域名解析 域名解析是为了方便记忆，DNS服务器将容易记住的域名解析成ip，当人们访问web站点时，不需要记住ip地址，只需要输入域名就可以直接访问到。 域名解析过程 在internet上的计算机是通过ip地址来定位的，给出一个ip地址，就可以找到与之对应的主机，但是ip数串是难记的，就发明了域名来代替ip地址，但是通过域名并不能访问到主机，中间添加一个依据域名来查找ip地址的过程，这个过程就是域名解析。 高速缓存DNS DNS服务器可以高速缓存从其他DNS服务器收到DNS记录，也可以在DNS客户服务器中使用高速缓存，将其作为DNS 客户端保存在最近的查询过程中得到的信息高速缓存的方法。 高速缓存DNS的作用 当一个主机第一次访问一个网页时，该主机的DNS服务器从远处的服务器拿到数据（address

When using an internet facing ELB, do all of the instances behind the load-balancer have to have their own public IPs?

由 寵の児 提交于 2019-12-10 16:07:22
问题 I'm configuring internet facing load balancing on my AWS deployment and there's one issue I can't seem to get. I understand that ELB uses DNS records to load balance between the IPs of the instances, but do I have to assign elastic (public) IP addresses to my web servers? If I want to load balance between 10 internet facing web servers, do I really need 10 elastic IPs? Or is there a way to use ELB with one elastic IP and one DNS record? Thanks! 回答1: Your instances do not need their own

Pass timeout to socket.getaddrinfo

由 与世无争的帅哥 提交于 2019-12-10 15:53:22
问题 Let's say I'm writing HTTP requests in Python and my DNS server goes down. If I try: import requests requests.get('https://api.twilio.com', timeout=3) and the DNS server is down, this can take upwards of 90 seconds, despite specifying a timeout value. Furthermore the blocking call is socket.getaddrinfo , and it doesn't look like this takes a timeout parameter. Is there a way to set a timeout on the DNS lookup? 回答1: There is no way to pass a timeout to the getaddrinfo system call, because it

A strange UnknownHostException

由 孤街醉人 提交于 2019-12-10 15:39:34
问题 In a web project . I see the log: hadoop.hbase.zookeeper.ZKConfig - java.net.UnknownHostException: example.com at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method) at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:850) at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1201) at java.net.InetAddress.getAllByName0(InetAddress.java:1154) at java.net.InetAddress.getAllByName(InetAddress.java:1084) at java.net.InetAddress.getAllByName(InetAddress.java:1020) at

Linking Amazon Route 53 Domain Name to EC2 instance

由 China☆狼群 提交于 2019-12-10 15:29:44
问题 I have registered a domain name with Amazon Route53 and I'm trying to link it to an EC2 instance. I'm unable to do this successfully. I have read documentation many times over, I have looked at many tutorials online, I have read many stack overflow answers. I still haven't been able t figure it out. Help will be greatly appreciated. What I have done so far: Launched EC2 instance and installed LAMP stack. I'm running a web app on the instance. Associated an Elastic IP to the instance and I'm

WP7 Mango - How to get an IP address for a given hostname

由 别来无恙 提交于 2019-12-10 15:26:51
问题 I need to get an IP address for a given hostname from a DnsEndPoint, and convert it to an IPEndPoint. How would I go about doing this? WP7 lacks a Dns.GetHostEntry function, so is there any way to do this without creating a Socket, sending data to the host, then receiving a ping from the host and reading the RemoteEndPoint property to get the IP address of the host? 回答1: Try using DeviceNetworkInformation.ResolveHostNameAsync in the Microsoft.Phone.Net.NetworkInformation namespace, like this:

Getting domain in AS3

由 ε祈祈猫儿з 提交于 2019-12-10 15:15:52
问题 I know how to get the URL of the page, but how can I extract simply the domain and the domain alone? It must return the same value with or without www, and it must also return the same value regardless of file, with or without trailing slash, etc. So www.domain.com would return domain.com , and domain.com/index.php would return the same as well. Is this possible? If so, is there a way to do it without calling ExternalInterface.call('window.location.href.toString') ? Thank you for the help!

How to detect DNS lookup error in JavaScript

由 為{幸葍}努か 提交于 2019-12-10 14:44:17
问题 I was wondering is there a way to detect DNS lookup error in JavaScript. is there some code or some trick work ? or this is a mission impossible? can somebody shed light on this? thanks a lot! 回答1: It's not possible to accurately predict what behavior will occurr when there's a 'DNS Lookup failure' on a random end-user's machine. For example, many ISPs return their own 'helper' search pages/sites when a lookup is performed on a non-existant domain (NXDOMAIN). This is also known as DNS
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