In this article we go through how to prepare the system in order to run dnsmasq and also how to configure the latter as a caching-only DNS server. A configuration file is also provided as a drop-in replacement for the default dnsmasq. Small modifications of the invoked commands may be needed for Debian, Ubuntu and other systems. There is some controversy about the real benefits of using a caching name server in a system, either desktop or server.
In this article we keep controversy out of the discussion and focus on the performance improvement the caching of DNS information can offer to a system while performing specific tasks.
For instance, a caching nameserver allows a web browser to acquire DNS information from the local DNS cache, provided that this information has already been cached, without the need to access any public DNS servers, which results in faster web browsing. Similarly, in a server environment, services like spam filters often need to perform many DNS queries for the same hostnames.
The latency of the communication with the remote nameserver may add up to the total time of email processing. There are lighter solutions, even all-in-one software like dnsmasqthat seem to be more suitable for setting up local DNS caching. By default, this user is nobody.
We use a dedicated system user to run dnsmasq. Run the following commands as root to create such an unprivileged system user and group named dnsmasq :. Here we write this file from scratch, so if you need to keep a copy of the original that ships with your distribution, do so with:.MikroTik RouterOS How to Setup DNS, DNS Cache and Securing it
First of all, we set some options regarding the basic server operation like the interface and port on which it should bind, the unprivileged user that should run the service and a PID file:. The bind-interfaces directive instructs dnsmasq to bind only to the network interface specified in the listen-address directive. We go with the defaults here, but keep in mind that a separate log file can be set as it is shown in the configuration snippet below currently commented out :. Logging to file requires some extra configuration for proper log rotation.
For more information, please read Appendix II. The following directives prevent dnsmasq from forwarding plain names without any dots or addresses in the non-routed address space to the parent nameservers. If this is not what you want, then take a look at the expand-hosts and domain directives.
Set the maximum number of concurrent DNS queries. The default value is Adjust to your needs. Set the size of the dnsmasq cache. The default is to keep hostnames. By setting the cache size to 0 disables the feature this is not what we really want. Again, adjust this value according to your needs.
The following directive controls whether negative caching should be enabled or not.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. Currently, 40 of these pods are kube-dns pods, each with m requests of CPU.
Yes, I had to scale it a lot. I'm currently trying to figure out why I do need so much of them, one thing that I did today was to take a look at prometheus metrics exposed by the sidecar container and observed that:. The way the client pod resolv. We also have an auto path function in CoreDNS that could make a difference, depending on your answers to the questions above. There are some weird edge cases with that though I am still working on the blog to make those clear; I do believe they are very unlikely cases for the most part.
Ok, if it were disabled you would see -N or --no-negcacheso in fact it is enabled. But it may be that the TTL isn't being set by kube-dns so then it's not caching those.
Using service. So without negative caching that doubles the query load but is necessary of course if things aren't in the same namespace. Even with negative caching it doubles the load - but they hit dnsmasq not kube-dns. Also the caching of the external responses will help but only in the sense that the last of the 5 or so queries will hit that cache.
For example, even if google. Fyi, using only fqdns made my cache hit rate way bigger, I've also allocated more memory for dnsmasq pod and set cache size to 64k, I was able to go from 40 kube-dns pods to only 10 doing that I think I could set it even lower.
I also observe this. Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.
Sign up. New issue. Jump to bottom. Copy link Quote reply. This comment has been minimized.It can serve the names of local machines which are not in the global DNS. Basic DNS Setup First things first, let's install the package: apt-get update apt-get install dnsmasq If your goal was to set up a simple DNS server, you just succeeded.
To test it, use your favorite DNS lookup tool pointed at localhost: dig debian. See Debian Reference or the resolv. Choosing Your Interfaces One you will probably want to do is tell dnsmasq which ethernet interface it can and cannot listen on, as we really don't want it listening on the internet. I personally wouldn't recommend this, as it gives those evil guys a few doors to try to break into. This is a good thing, as you could bring down whatever network you are connected to if you are not careful.
In the example above, this server would hand out address starting at The last number is how long the DHCP leases are good for. In this example, they would be good for twelve hours. The aren't necessary, but definately help once you start playing with more advanced configurations. It also helps me remember which range is which. Do not use this configuration if you use different network e. The dnsmasq 8 man page suggests the following: In order to configure dnsmasq to act as cache for the host on which it is running, put "nameserver Exaclty how to do this depends on the method s of network configuration in use.
If you're using DHCP, then instruct your client to prepend Useful to protect a laptop from potentially hostile networks.
Wiki Login. Hosting provided by Metropolitan Area Network Darmstadt.Alright, so you already have your own NextCloudPi server or any other similar service at home. You also registered for Dynamic DNS with no-ip. You can configure your Android or laptop sync client for NextCloud with your flashy new dynamic DNS domain, so you can access to your private cloud at home from outside, but depending on the modem-router provided by your ISP, you will find that you might not be able to access through URL from inside your house.
This happens because your router does not support NAT loopbackso it is unable to access the server inside your house with the public IP address that you use from outside your house. Most home routers lack this feature. The solution to this is to set up your own DNS server inside your house, and point all of your devices to it.
You then have the ability to configure it to direct any queries to mycloud. For this, we will use the dnsmasq daemon. It is a very compact little server that also has the ability to provide DHCP and more, but here we will use it as a DNS redirect server with cache. A nice upside is that we will achieve DNS caching, so we will accelerate all the internet lookups inside our home! More on that later. There are two options for configuration, depending on wether you are installing it in your already set up and running Raspberry Pi online installationor if you use the NextCloudPi image.
See details below, but the configuration is exactly the same. If you can do this, no further configuration is needed. For your Android, you will sadly need to configure a static address. Whenever you are outside of your house, the local address will have no configured route, so it will use the secondary DNS provider without any speed penalty.
First, clone the repo. Use the generic software installer with the script dnsmasq. You can do this process offline using QEMU. In order to check that it works, you can use the dig utility from the bind-tools package. You can verify that the query went through your dnsmasq server in This time the query is cached, so our RPi will answer directly with the IP associated to the URL, and it will be way faster, we went down to 0 milliseconds!
Rich content websites can be constantly querying different URLs and a single website can be loaded by the combination of many HTTP requests. In this cases, the performance benefit of having cached DNS results will be more noticeable.
If you would like to provide a URL for a particular IP in your local network, you can specify this in two ways.
You can also set up dnsmasq as a local DNS cache for your computer. Humbly sharing things that I find useful [ github dockerhub ] View all posts by nachoparker. I have not found any method in the forum or on the web in general that works — everything seems to send me to what I think is a help page for my router. Ignoring the warning I did change it by hand and yes it did get overwritten!
The server responds to the query, but the response time is exactly the same as the Cloudflare DNS. I don't try I have tried dig facebook. You don't need the cloudflare DNS servers here. You can add them in the configuration files that dnsmasq uses. Then, configure dnsmasq in dnsmasq.
Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Asked 1 year, 4 months ago. Active 1 month ago. Viewed 1k times.
Caching with DNSMasq and optionally with DNSSEC
Paolo Bertolli Paolo Bertolli 1 3 3 bronze badges. Active Oldest Votes. If you really want to use your dnsmasq as caching DNS and also allow the rest of the LAN to connect to it: Remove the upstream nameservers from your resolv. Fanatique Fanatique 1 1 silver badge 12 12 bronze badges. I have followed your instructions and this is the results. Ok after several proof I have discovered that dnsmasq runs for the local For other device the time increase, but in any case less than the previous time.
Server Fault is a question and answer site for system and network administrators. It only takes a minute to sign up. I looked up the man page and couldn't find how long dnsmasq cache a dns. I am having a problem that request send to an external service sometimes takes over 5 or 10 seconds for namelookup. Installing Dnsmasq improves name lookup but slow namelookup still happens with less frequency.
One solution is to setup a simple ping in cron job but I need to find out the expiration time first. The option you will need to set for dnsmasq is --min-cache-ttlthe value is in seconds. The TTL for api. I'm guessing you are located in China. See the dnsmasq mailing list message detailing the introduction of this feature. Sign up to join this community. The best answers are voted up and rise to the top.
Home Questions Tags Users Unanswered. How long does dnsmasq cache dns? Ask Question.
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Asked 4 years, 9 months ago. Active 4 years, 9 months ago. Viewed 25k times. I have posted another dig output. Active Oldest Votes. Tero Kilkanen Tero Kilkanen Do you mean that dnsmasq only cache dns within the TTL period? I updated my question with the dig output. Yes, only the TTL period is used for caching. However, as stated in the manual, you can use --max-cache-ttl to force lower TTL for cached values haven't tested it myself.
TeroKilkanen Query time: 0msec means a cache hit to dnsmasq.It is designed to be lightweight and have a small footprint, suitable for resource constrained routers and firewalls. Install the dnsmasq package.
The file contains comments explaining the options. For all available options see dnsmasq 8. To set up dnsmasq as a DNS caching daemon on a single computer specify a listen-address directive, adding in the localhost IP address:.
See dnsmasq 8 for more options you might want to use. This causes all queries to be sent to dnsmasq. Since dnsmasq is a stub resolver not a recursive resolver you must set up forwarding to an external DNS server.
This can be done automatically by using openresolv or by manually specifying the DNS server address in dnsmasq's configuration.
Run resolvconf -u so that the configuration files get created. If the files do not exist dnsmasq. Now DNS queries will be resolved with dnsmasq, only checking external servers if it cannot answer the query from its cache. To do a lookup speed test choose a website that has not been visited since dnsmasq has been started drill is part of the ldns package :. Running the command again will use the cached DNS IP and result in a faster lookup time if dnsmasq is setup correctly:.
This article or section needs expansion. By default dnsmasq has the DHCP functionality turned off, if you want to use it you must turn it on. Here are the important settings:. See dnsmasq 8 for more options. From a computer that is connected to the one with dnsmasq on it, configure it to use DHCP for automatic IP address assignment, then attempt to log into the network normally.
To use it, create a directory for TFTP root e.
How to configure Dnsmasq caching DNS server in Linux
For increased security it is advised to use dnsmasq's TFTP secure mode. In secure mode only files owned by the dnsmasq user will be served over TFTP. You will need to chown TFTP root and all files in it to dnsmasq user to use this feature. The rest is up to the bootloader. In some cases, such as when operating a captive portal, it can be useful to resolve specific domains names to a hard-coded set of addresses.
This is done with the address config:. To do this staticly, server per interface, use interface and bind-interface options. This enforce start second dnsmasq. To blacklist domains, i. For ease of use place the blacklist in a separate file, e. Related articles Domain name resolution.
Warning: dnsmasq's default configuration enables its DNS server. Note: file paths are relative to TFTP root if the file has a. Note: In case pxe-service does not work especially for UEFI-based clientscombination of dhcp-match and dhcp-boot can be used. See RFC for more client-arch numbers for use with dhcp boot protocol.