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Mastering Development System & Network

Different source IPs when connecting to AWS instances in same AZ

When connecting to my AWS instances in the same AZ, I am able to connect to some instances and not others even though all instances were using the same NACL an Security Groups. My security groups were set up to allow all traffic from my IP address which I obtained by running the following on […]

Categories
Mastering Development System & Network

Different source IPs when connecting to AWS instances in same AZ

When connecting to my AWS instances in the same AZ, I am able to connect to some instances and not others even though all instances were using the same NACL an Security Groups. My security groups were set up to allow all traffic from my IP address which I obtained by running the following on […]

Categories
Mastering Development System & Network

apache redirector to redirect custom url to aws internal dns name

I am using reverse proxy redirecting to internal DNS name of load balancer. As the internal DNS name of Load balancer is too long, I am getting an error ProxyPass worker hostname (internal-xxxxxx-xxxxxx.xxxxxx-xxxxx.xxxx.com) too long I am trying to use redirector rule, Redirect “xxxx” “internal-xxxxxx-xxxxxx.xxxxxx-xxxxx.xxxx.com” In my ProxyPass, I used <IfModule mod_proxy.c> ProxyPass / https://xxxx:443/ […]

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Mastering Development System & Network

Configure Multiple Servers for SMTP in Exim

How do I set up an SMTP server with Exim to send emails through multiple servers with different IPs? This service will only be used to send emails from a SaaS platform, and an email client will never be configured to connect to these servers.

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Mastering Development System & Network

Website redirection intermittently work in Firefox but not work at all in IE

After few try an error in website redirection, I manage to perform website redirection but it intermittently works in Firefox but not work at all in IE. I manage to clear all cache and retry in Firefox and it works, but weirdly it does not work after that. I confirmed that I wasn’t doing any […]

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Mastering Development System & Network

ALB writing to 2 postgre sql instances

I have nginx and postgre sql running on the same ec2 instance. It serves a rails app that reads and writes data on that db. I would like to have 2 instances behind an ALB service to distribute load and ensure availability. What should I do to ensure data is consistent across the 2 instances?

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Mastering Development System & Network

Asterisk: Using Queue() in the h extension

I’m trying to get users to be able to record a message, hangup and have the call continue and dial Queues and playback the recording. I’ve gotten most of the way there, but right now when I call Queue() in the h extension it hangs up immediately (the queue members do get the call for […]

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Mastering Development System & Network

What http caches have full support for http/2?

Planning a tech stack and finding scant mentions of http/2 in documentation on latest versions of varnish and squid. Am I missing something, or is it actually difficult to put up a cache for http/2? What http caches explicitly support http/2?

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Mastering Development System & Network

MySQL crashes after upgrade to mysql 8

After we upgraded our database to MySQL 8, one query stopped working and is causing the database to crash. MySQL version 8.0.19, before: 5.7 Error.log output: Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (7f85d0240968): is an invalid pointer Connection ID (thread ID): 11 Status: NOT_KILLED […]

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Mastering Development System & Network

GPG disabling ssh support for an authentication key coming from a smartcard

When a gpg smartcard (e.g. yubikey) is inserted and contains an authentication key, the key is automatically enrolled by the gpg-agent. That means the key is usable for any ssh operation without needing to add its keygrip inside the file ~/.gnupg/sshcontrol. Source: Agent-Configuration documentation (look after the last line of text inside the sshcontrol paragraph) […]