My registrar tell me that I can't have a CNAME record that doesn't start with www. Is it true?  So I am using amazon ec2 with load balancing. the loadbalancer has a convoluted DNS name, and specifically tells you to use a CNAME to send requests to that DNS name, and not an A record.     myloadbalancer-1234567890.us-west-1.elb.amazonaws.com (A Record)      Note: Because the set of IP addresses associated with a LoadBalancer can change over time, you should never create an "A" record with any specific IP address. If you want to use a friendly DNS name for your load balancer instead of the name generated by the Elastic Load Balancing service, you should create a CNAME record for the LoadBalancer DNS name, or use Amazon Route 53 to create a hosted zone. For more information, see Using Domain Names With Elastic Load Balancing.   I purchased a domain. The registrar doesn't allow you to add records yourself, only by emailing them a request. So they set up a CNAME record  mydomain.org  SOA 111  whatever www.mydomain.org    CNAME   3596    myloadbalancer-1234567890.us-west-1.elb.amazonaws.com      when I asked them why it doesn't work with www, the registrar answered that there is a technical prohibition to make a CNAME record without www. Is it true, or are they incompetent/lying and I should switch registrars?
This is a  about CNAMEs at the apices (or roots) of zones   It's relatively common knowledge that CNAME records at the apex of a domain are a taboo practice.  Example: example.com. IN CNAME ithurts.example.net.  In a best case scenario nameserver software might refuse to load the configuration, and in the worst case it might accept this configuration and invalidate the configuration for example.com.  Recently I had a webhosting company pass instructions to a business unit that we needed to CNAME the apex of our domain to a new record. Knowing that this would be a suicide config when fed to BIND, I advised them that we would not be able to comply and that this was bunk advice in general. The webhosting company took the stance that it is not outright forbidden by standard defining RFCs and that their software supports it. If we could not CNAME the apex, their advice was to have no apex record at all and they would not provide a redirecting webserver. ...What?  Most of us know that  insists that A CNAME record is not allowed to coexist with any other data., but let's be honest with ourselves here, that RFC is only Informational. The closest I know to verbiage that forbids the practice is from :     If a CNAME RR is present at a node, no other data should be   present; this ensures that the data for a canonical name and its aliases   cannot be different.   Unfortunately I've been in the industry long enough to know that "should not" is not the same as "must not", and that's enough rope for most software designers to hang themselves with. Knowing that anything short of a concise link to a slam dunk would be a waste of my time, I ended up letting the company get away with a scolding for recommending configurations that could break commonly used software without proper disclosure.  This brings us to the Q&amp;A. For once I'd like us to get really technical about the insanity of apex CNAMEs, and not skirt around the issue like we usually do when someone posts on the subject.  is off limits, as are any other Informational RFC applicable here that I didn't think of. Let's shut this baby down.
The Wikipedia page () proves that $$f(x) = \begin{cases}  \exp(-1/x),  &amp; \mbox{if }x&gt;0 \\ 0, &amp; \mbox{if }x\le0 \end{cases}$$ is a non-analytic smooth function. But I don't understand why the fact that "the Taylor series of $f$ at the origin converges everywhere [where does "everywhere" mean here?] to $0$" implies the Taylor series converges to $0$ when $x&gt;0$? Can someone explain this in greater detail? I guess there should be a gap in my understanding of power series. Launchers for installed snap applications (including Ubuntu Software) disappeared after installing GNOME Software What is the limiting factor in lens construction when it comes to f-stop values? The number of divisors I am reading a math book. It states the following rule:      For an integer $n$ greater than 1, let the prime factorization of $n$ be $$n=p^a_1p^b_2p^c_3...p^m_k$$    Here $a, b, c,..., m$ are nonnegative integers, and $p_1,p_1,...,p_k$ are prime numbers. Then the number of divisors of $n$ is: $$d(n)=(a+1)(b+1)(c+1)...(m+1)$$   I can use the rule to solve problems correctly, but I don't understand the rule. How to prove it? I shall assume that the sun is at rest, so before the half mass disappear, the orbit of earth is an ellipse. Elected moderators can nominate themselves , and I can nominate myself again, despite having won the first round of election.    I understand this isn't going to be easy to fix, given that SE only knows about community mods, employees and developer roles, and pro-tempore mods need to be able to nominate themselves. Should I have more than one brokerage account? I have my brokerage business with one particular well-known US brokerage house. I find being able to access my retirement accounts and personal investment accounts through the one interface useful.  However, I was talking with a friend of mine and she said she never puts more than about $50k into any particular brokerage account.  Managing three or four such accounts seems like too much overhead for me. I'd prefer to spend my "investment time" reading up on my investments and researching new ones.  One reason to have more than one brokerage account with different houses is the issue of  insurance:     Within limits, SIPC expedites the return of missing customer property by protecting each customer up to $500,000 for securities and cash (including a $250,000 limit for cash only).   What other reasons could I have to use more than one brokerage account? Principal component analysis "backwards": how much variance of the data is explained by a given linear combination of the variables? I have carried out a principal components analysis of six variables $A$, $B$, $C$, $D$, $E$ and $F$. If I understand correctly, unrotated PC1 tells me what linear combination of these variables describes/explains the most variance in the data and PC2 tells me what linear combination of these variables describes the next most variance in the data and so on.   I'm just curious -- is there any way of doing this "backwards"? Let's say I choose some linear combination of these variables -- e.g. $A+2B+5C$, could I work out how much variance in the data this describes? When to use "have" and "have got" About compactness and completeness of set $X = \mathbb{R}$ with the metric $d(x, y) = \frac{|x-y|}{1+|x-y|}$ Converting mxd to earlier version using ArcPy? 24% tax on first pay in the UK? Quite a similar thread to others I've seen here - hope I'm not repeating the same questions again!   I just got my first payslip after arriving in the UK and noticed that the tax is far higher than the HMRC rate for my salary bracket.     I did some research but couldn't find any reason why I would be taxed at 24.23% of my gross this month AND then an additional amount for NI.    I have about £640 back pay from April that is only being paid now,but even so, it doesn't explain the rather large discrepancy between the HMRC rate and what I'm seeing here.   Any ideas? Accessing Reduce from DSolve Can we get x comment votes per y minutes, rather than one vote per 5 seconds? I quite often will read a thread of comments, and want to vote up a few of them. I vote one up, read the next few comments, vote up another and get a *giant red box*.  I've seen that "You can only submit a comment vote every 5 seconds" box far too often. Can I vote for 12 comments per minute, rather than 1 comment every 5 seconds? When a/an precedes a parenthetical aside (sometimes seen in informal/conversational writing), should the vowel rule depend on the first word in parentheses, or the next word in the "regular" flow of the sentence?     I need a (memorable) idiom (preceding an m word; use a)   or     I need an (memorable) idiom (preceding an i word; use an) What is $\sqrt{i}$? If $i=\sqrt{-1}$, is $\large\sqrt{i}$ imaginary?     Is it used or considered often in mathematics? How is it notated? Make a Bash alias that takes a parameter? Simplify result of $\int_0^{\infty} \frac{1}{1+x^n}dx$ It is quite easy to show that (by using residue theorem) $$\int_0^{\infty} \frac{1}{1+x^n}dx = \frac{2 \pi i^{1+2/n}}{n(e^{2 \pi i / n} - 1)} $$ for $$n \ge 2$$  Is there any possibility to simplify $$\frac{2 \pi i^{1+2/n}}{n(e^{2 \pi i / n} - 1)}$$ or it is best result?  Thanks in advance! Are the square roots of all non-perfect squares irrational? Move iTunes folder outside Music folder iTunes by default stores its settings, the iTunes Library.itl file, and the music library audio tracks, inside the \Users\username\Music\iTunes folder.  I don't want my Music folder polluted with program settings, especially because I'm synchronizing that folder on the cloud. Via the settings panel I can only change the path of the audio tracks, but the settings remain in the default position.  Is there a way to completely move the iTunes folder to another path?  PS: I've looked at the answers to , but the focus there is on moving the media library only, not the whole iTunes directory.