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I'm not even sure if this is a programming question, a networking question, a Windows question...
I'm completely at a loss of where to look!
I'm developing a web app with a service in ASP.NET 8, both need a subdomain.
So I have sub.localhost:1234 for the web app and sub.localhost:5678 for the service.
I can access both in my browser, but my web app can't access the service ("no such host is known").
When I'm at home, it works.
When I'm at home and on VPN it doesn't work.
It works with and without VPN for my coworker, but only from home.
At the office, it doesn't work with or without VPN for both of us.
At first I though the VPN was the problem because at home it worked without the VPN, but today I'm at the office and it doesn't work at all (even though I developed this service at the office!).
We've deployed both in an Azure app service with the subdomain properly registered in the DNS and a valid certificate.
The web app can't access the service, again because "no such host is known".
We can, however, access the service in Azure from our development environment (sub.localhost:1234), but for me only without VPN and for my coworker only with VPN and only from home.
We can access the service from its Azure domain (e.g. myservice.azurewebsites.net).
The plot thickens, because for my coworker one specific controller does seem to work at the office, but not from home (it doesn't work for me at all).
The controller isn't particularly interesting.
When I remove the subdomain everything works.
It seems completely random and I can't even think of where to look...
At least I can rule out it's not a firewall issue (turned it off completely with no result).
Has anyone seen this before or have a clue of where to look?
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sub.localhost makes no sense to me at all.
If we are saying localhost, it's a given that everything is at 127.0.0.1.
Maybe there is some reason you need *different* domains though for local app<->service.
In that case, I would ditch sub.localhost and go with something more akin:
myappservice 127.0.0.1
myapp 127.0.0.1
added to %windir%/system/drivers/etc/hosts
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The sub domain is any customer location code.
So it's loc1.localhost or loc2.localhost.
I've thought about the hosts file, but that won't explain why it works in my browser, but I can't ping it and why it works at home, but not at the office and that my coworker has a varying mileage.
It doesn't work in Azure either, which is even weirder, since all subdomains are registered in a DNS within a "proper" domain.
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Hmm, localhost is not technically a domain name, so I guess that is why it is elephanting when trying to resolve a sub domain from it.
Two things I can think of to try:
1. use sub.127.0.0.1:1234 (or possibly sub."127.0.0.1":1234
2. add sub.localhost to your hosts file. (pointing to 127.0.0.1 or localhost)
Good luck
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RainHat wrote: so I guess that is why it is elephanting when trying to resolve a sub domain from it
But only under specific (unknown) circumstances, like being at the office or having a VPN.
I've thought about the hosts file, but that won't explain why it works in my browser, but I can't ping it and why it works at home, but not at the office and that my coworker has a varying mileage.
It doesn't work in Azure either, which is even weirder, since all subdomains are registered in a DNS within a "proper" domain.
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From comments at top of hosts file:
# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
# ::1 localhost
If I add a line to hosts file:
127.0.0.2 sub.localhost
then I can do:
>ping sub.localhost
Pinging sub.localhost [127.0.0.2] with 32 bytes of data:
Reply from 127.0.0.2: bytes=32 time<1ms TTL=128
Mircea
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I've thought about the hosts file, but that won't explain why it works in my browser, but I can't ping it and why it works at home, but not at the office and that my coworker has a varying mileage.
It doesn't work in Azure either, which is even weirder, since all subdomains are registered in a DNS within a "proper" domain.
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I think at least some browsers (Chrome, I'm looking at you!) have their own DNS resolver. VPN adds another level of weirdness and anyway localhost is not a valid domain name. Are you trying to solve all the possible interactions between these parts or you just want your app to work? If it's the first one, I'd like to hear the result, maybe in an article or tip here. If it's the second, just add a line to your hosts file. It has the highest priority in the DNS resolving order[^] and it just works.
Mircea
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Wordle 1,084 4/6*
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"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!
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Wordle 1,084 2/6
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Wordle 1,084 4/6
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β¬β¬β¬π¨π¨
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In a closed society where everybody's guilty, the only crime is getting caught. In a world of thieves, the only final sin is stupidity. - Hunter S Thompson - RIP
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Wordle 1,084 4/6*
β¬π¨β¬β¬π¨
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Happiness will never come to those who fail to appreciate what they already have. -Anon
And those who were seen dancing were thought to be insane by those who could not hear the music. -Frederick Nietzsche
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Wordle 1,084 4/6
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Ok, I have had my coffee, so you can all come out now!
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I hope this is not going to be called programming question, but I am running out of non AI forums to post this.( This forum Linux subforum is of no help - this is not programming issue )
I just had a total "no boot" failure of my grub file - working multi-operating system.
( Total power outage / failure caused this)
Ever since I started using Linux Ubuntu I have been unable to figure out HOW TO MAKE FULL DUPLICATE of perfectly working OS. ( Using "DD" command did not work!) I have several HD, space in no issue.
I was hoping use something likes RAID to do this. I am well aware of RAID issues, but I am desperate to have this resolved before another catastrophic failure.
PS
This time my working grub recovered because another , non used , but operational Ubuntu grub file was "updated/ upgraded".
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I think the title of your post is hilarious because it sounds so much like when people ask (quite frequently,) "How to solve this problem?" and it's a question that would take pages and pages to answer.
The difficult we do right away...
...the impossible takes slightly longer.
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Perhaps I am on wrong planet- I was under the impression this forum, in particular, was in existence to help solve problems. I guess I am wrong ... again.
But I do appreciate your post for staying on the subject and
you not telling me to RTFM or "get an new one ".
Hope somebody will take "the first baby step" to start the mentioned pages leading to solution.
PS
Just went thru few "fsck" to fully (?) recover from the grub failure...
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There are many packages out there that can duplicate an entire partition or an entire disk. Many of them have a version that can be installed on a boot CD (or USB drive). OriginalGriff swears by AOMEI (runs on Windows, or from a Windows PE boot disk), but there are others.
AIUI, the grub is not part of any partition, so duplicating the partition is insufficient to recover the O/S. It is better to duplicate the entire disk, assuming that you have space available. As far as recovering the grub is concerned, I would assume that you start from a boot CD (or USB drive) containing the appropriate version of Ubuntu, but I'm unsure as to how to progress from there. 
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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Relax blend in.
Veeam Agent is your friend. No matter what the OS.
4 letter word beginning with F: Free. (community).
Clonezilla is also good.
>64
Itβs weird being the same age as old people. Live every day like it is your last; one day, it will be.
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I understand that the OP intends to reload the backed up OS to the same machine. Then a backup might work, as long as the hardware is completely unchanged.
Usually, the binary OS running on a machine is closely tailored to the hardware, e.g. the selection of drivers. It doesn't carry drivers it doesn't need. Say that a lightening hit your internet line (presumably a metallic one, not a fiber); the high voltage made it all the way to your network interface and blew it. So you replace the broken interface with a new one, of a different model. Your OS doesn't have a driver for it, preventing you from retrieving the correct driver from internet.
Or if the lightening spike went through your power supply and hit your disk, and you replace it with a newer model, requiring a different driver. The OS lacks the driver to boot itself from the disk, even if the complete OS (but with the old disk driver) is available.
Fortunately, hardware interfaces have become much more standardized today than 20 years ago. E.g. no USB memory stick requires any special driver. Yet our PCs run numerous hardware dependent drivers. Even though your PC may boot, some essential equipment may fail to operate with the backup OS.
Years ago, after buying a new mainboard for my PC (transferring a lot of stuff from the old one - this was in the days when you had plug-in cards for everything), I tried to take a shortcut, loading the total backup I had made before throwing out the old mainboard. It "sort of" booted, but lots of stuff didn't work (even though it was unchanged; it probably had been assigned other interrupts something of that kind), and the OS bluescreened several times before I gave up and went through a complete OS installation from scratch.
There are also those software packages (OS or other) that reads some machine identification, such as a CPU ID or a hash of the IDs of peripheral IDs, and refuse to run if you try to install the backup on another CPU or configuration. A couple of Windows versions did this. If you added another hard disk to your PC, you had to call Microsoft service to receive another activation code for the new configuration. This was so annoying that it was first loosened a lot, then removed completely.
I don't expect anything of that kind with Linux, though. But even if the OS core is free, there is a lot of commercial software running on Linux, and the vendors may use such mechanisms to prevent unauthorized use of their software.
Religious freedom is the freedom to say that two plus two make five.
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If you have the drives and your concern is just having backups/never really having the machine down, just slap three in there in RAID0+1 and call it awesome.
You could just go RAID 1, but you'll get a slight performance bonus the first way.
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Hey everyone,
I've been diving into C# .NET recently and I couldn't help but notice some similarities with C programming. I'm curious about how much C programming principles influence C# .NET and how understanding C might help in mastering C#.
Key Points of Discussion:
Syntax and Basic Constructs:
C# shares many basic syntax elements with C, such as data types (int, char, float), control structures (if, for, while), and operators (+, -, *, /). How much does familiarity with these elements in C help when learning C#?
Memory Management:
C provides manual memory management using malloc and free, whereas C# handles memory through garbage collection. How does this difference impact the way we write and optimize code in C# compared to C?
Pointers and References:
While C heavily relies on pointers, C# abstracts memory management but still allows the use of pointers in an unsafe context. How relevant are C pointers when dealing with C# programming, especially in performance-critical applications?
Object-Oriented Programming:
C# is inherently object-oriented, unlike C. For those coming from a C background, how challenging is it to grasp the object-oriented concepts in C#? How can C principles aid in understanding these concepts?
Platform Independence:
C# through .NET Core aims to be platform-independent, much like C programs can be compiled on various platforms. What are the key differences in achieving platform independence between the two languages?
Use Cases and Applications:
C is often used for system-level programming and embedded systems, while C# is popular for web applications, desktop applications, and game development using Unity. How do these different use cases affect the choice of language and the transition from C to C#?
Your Experiences and Insights:
Iβd love to hear from those of you who have experience in both C and C#. How did your knowledge of C help (or not help) you when learning C#? Are there specific areas where you felt a strong correlation or significant differences? Any tips for someone coming from a C background and looking to excel in C# .NET?
Looking forward to an engaging discussion!
Cheers,
Tejaswini
modified 13hrs ago.
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...this feels like a test. Are you trying to get us to do your homework?
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