Tag Archives: DNS

AWS: Route53 Private Hosted Zones — hiding domains from the Internet

26 July 2021
 

 Private Hosted Zone in AWS Route53 allows to limit access to DNS records of a domain, thus making it inaccessible for the DNS Enumeration (or DNS brute-force), when an attacker checks for available records in a domain to know endpoints list to check them for vulnerabilities. For such attacks, there is a lot of utilities… Read More »

Kubernetes: NodeLocal DNS and the “lookup istiod.istio-system.svc on lookup: no such host” error

19 April 2021
 

 In our Deployments, we are using the NodeLocal DNS as a local DNS cache to reduce requests number to the AWS VPC DNS, see the Kubernetes: load-testing and high-load tuning – problems and solutions for details. Currently, a manifest looks like the next: … dnsPolicy: “None” dnsConfig: nameservers: – 169.254.20.10 … The problem is, that… Read More »

Kubernetes: update AWS Route53 DNS from an Ingress

22 November 2020
 

 We’d like to have the ability to add a DNS-record on the AWS Route53 when a Kubernetes Ingress resource is deployed and point this record to the URL of an AWS Load Balancer which is created by the ALB Ingress controller. To achieve this, the ExternalDNS can be used which will make API-requests to the… Read More »

AWS Elastic Kubernetes Service: load-testing and high-load tuning – problems and solutions

4 September 2020
 

 Actually, this post was planned as a short note about using NodeAffinity for Kubernetes Pod: But then, as often happens, after starting writing about one thing, I faced another, and then another one, and as a result – I made this long-read post about Kubernetes load-testing. So, I’ve started about NodeAffinity, but then wondered how… Read More »

Grafana: Loki – the LogQL’s Prometheus-like counters, aggregation functions and dnsmasq’s requests graphs

17 November 2019
 

 The last time I configured Loki for logs collecting and monitoring was in February 2019 – almost a year ago, see the Grafana Labs: Loki – logs collecting and monitoring system post, when Loki was in its Beta state. Now we faced with outgoing traffic issues in our Production environments and can’t find who guilty for… Read More »

dnsmasq: AWS – “Temporary failure in name resolution”, logs, debug and dnsmasq cache size

28 October 2019
 

 We are using AWS VPC DNS and sometimes facing with errors like “php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution“. The only advice from AWS tech. support was to configure a local dnsmasq service to act as a local DNS cache, but I did this already year ago and this issue happens once in 1-2-3… Read More »

OpenVPN: Let’s Encrypt DNS verification on AWS Route53 and OpenVPN Access Server SSL certificate auto update

24 May 2019
 

 In addition to the OpenVPN: SSL and hostname configuration post about OpenVPN Access Server, set up and configuration. So, three months passed and it’s time to renew Let’s Encrypt SSL certificate (see. Prometheus: Alertmanager и blackbox-exporter — проверка срока действия SSL и нотификация в Slack, Rus). I could use a well-know for me scheme with… Read More »

AWS: VPC peering DNS resolution and DNS settings for OpenVPN Access Server

17 May 2019
 

 We have a VPC with OpenVPN Access Server running. This VPC is connected with other VPCs in our AWS account. The issue is that currently when a user is connected to VPN for the DNS resolution into EC2 instances private IPswe are using dnsmasq service on the VPN-host which has a /etc/dnsmasq.hosts file where are manually… Read More »

Arch Linux: OpenVPN – resolv.conf is not updated

2 March 2019
 

 On an Arch Linux setup – local resolv.conf not updated after connection to OpenVPN AS. As far as I know – the problem is specific to Arch Linux and its “child’s” like Manjaro Linux installations. Local openvpn installed via pacman – see the OpenVPN: OpenVPN Access Server set up and AWS VPC peering configuration post for… Read More »