Why do mx records exist

Different servers usually form part of a domain. Besides the web server, which supplies the website, there is often also the FTP server, and in fact even one or more mail servers. All of them can be reached via different subdomains. The name of this subdomain can be requested via the MX record. This manages the mail server from which the email is sent, in most cases automatically. DNS records consist primarily of several units of information placed in different fields. This means that the content of each field is ostensibly completed with a period.

Actually, the FQDN maps the complete path to the root server — from the smallest unit located to the far left, to the largest situated to the far right.

The highest level is unnamed however, which is why there is nothing after the preceding period. The time to live specifies how long the requestor can hold and use the information in their cache.

This is intended to ensure that no outdated records are used. Should the time lapse, the client must again request the record from the name server. The TTL is specified in seconds. This field frequently does not appear in the actual record. Instead, the time for the complete zone is defined at the beginning of the zone file.

The class field is optional, as nowadays only the internet is possible. However, both networks are today no longer in operation. For this reason, the field remains either empty or invariably contains the IN abbreviation. The field relating to priority is a special feature of MX records. Many administrators — in particular those of larger projects — have several mail servers running in parallel.

In doing so, however, distribution is not necessarily supposed to occur evenly. For this reason, priorities can be assigned. The server with the lowest value has the highest priority and is selected first. The data field finally contains the mail server name. Sign up to join this community. The best answers are voted up and rise to the top.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why can't MX records point to an IP address? Ask Question. Asked 6 years, 9 months ago.

Active 6 years, 8 months ago. Viewed 58k times. But, in principle, why is this required? Improve this question. Michael Hampton k 38 38 gold badges silver badges bronze badges. If you can set up an MX record you can also set up an A record. I don't see the problem here. I just tried in CloudFlare. It doesn't accept IP address as a value for MX record. I had never cared about this until I added an SPF record, and had too many lookups. Had to find a different way to cut some out.

Add a comment. Active Oldest Votes. Improve this answer. Community Bot 1. Michael Hampton Michael Hampton k 38 38 gold badges silver badges bronze badges. I think the intention was to discourage the industry from using IP addresses en masse--which is likely what would have happened, had that rule not been stated--rather than on a case-by-case basis. Hence, "should", as opposed to "must". I had never considered most of that. Zenexer Traffic laws aren't there for the inconvenience of relatively few expert drivers who know exactly what's safe and what isn't.

I searched on google but I feel lost. Please provide me some advice or any concise link so that I can study and implement. I have a common scenario where we have an MX record that points to a SaaS provider for email filtering. Luckily the provider was pooling the emails and delivered them once their network came back online. What I want to do is put the power back in our hands and have a way to failover from the SaaS and go directly to us, bypassing the filter in the event this issue occurs again.

Is there a way to do this? I was doing some research. Would using round robin MX records with priorities solve this issue? For example:. The mail server sending the message would try either one of the 10 records first, then try the other, then try the 20 record if the first two failed.

Using SBS and Exchange which works fine. I am tripping over the disconnect between an MX record of mail. There is an A record for remote and mail pointing at same IP address.

I do not understand how this works. Ultimately I would like to put another 2 domains onto this server.. I have checked few General Domains and few Exchange Domain. Exchange server provide only 1 mxRecord and it start with either mx1 or smtp1 or webmail.

Does exchange always provide 1 mxRecord? You can configure as many as you need. All Domain mail send and received ok. DNS working perfectly. What i can do? Please advice me. Thank you for this article.

Eg; MX — mail. Hi Paul, Very good post! I have two domain names. The website of domain1. I went to the registrar and pointed the MX record of domain1. Then I logged into the cPanel of domain2. My server public MX records resolve just fine — but apparently the Microsoft connectivity analyzer only queries public MX records.

Exchange feels like bloated rush to market code hoping for the next daily critical update; just my. Any routing that occurs beyond that is invisible to the ExRCA. I have 2 CAS Servers that will be receiving email. So, should I create 2 MX records on Public dns. And with same priority or different priority. If one CAS server will get down, then the sending server will use another MX record to deliver the email to second Server.

Hi Paul, I have bought a domain from godaddy. When i bought this domain company. Now i have created a Host A with mail. Com There is no Reverse Lookup Entry yet has been created. Could you please advise if there is anything you think needs to be changed. I joined to new organization as a exchange admin, their the previous admin was left the company with out intimation, Can someone tell me how to check the complete mail routing process in exchange server and how to find the exact MX record in the domain and where the Mx records is configured.

What I get is a hard bounce if I sent the form results to any and all of the company emails saying that there is no such email account. So I go into the filters section of their Gmails and there are no filters, nothing in spam, no way to adjust or allow emails from the Gravity form. Any advice would be appreciated. The assumption they are making is that customers will use the free email accounts hosted on the server.

Which many do. If they are providing you a CPanel interface for your account there is an MX setting in there where you can tell it to always deliver locally vs always use the MX record.

The info in the bounce message is important, it will say which server rejected the message eg was it a Google server or a Hostmonster server…. Really this is something you should be able to sort out using their support. Thanks Paul, I was able to sort it out with your help by recreating all of the MX record fields in Hostmonster, deleting all of the Hostmonster free mail account defaults, and then switching the whole Webstarts DNS over with a simple full NS change.

What an ordeal to achieve what should have been a simple goal! I thank you for providing the clarity I needed to resolve this. RFC , section 5. The quote from the article is: "if no MX record for domain is present, look up for an A RR record, and if such record is present, treat it as an MX record".

I'm not guru enough to set the record straight, if required. Add a comment. Active Oldest Votes. Improve this answer. Alnitak Alnitak k 69 69 gold badges silver badges bronze badges.

Interesting side-effect of SRV records for http -- there's a natural failover to an error page or stale static server when your primary web server is completely unavailable. We need more of this. Dustin why there should be any kind of fallback implemented on DNS level?

This should be realized with other piece of software, like NAT router, which deal with ports and redirections by design. Alnitak I don't wanna play semantic game here - recorded, implemented, whatever Show 9 more comments. Not at all: the main purpose behind the MX records is, as explained by Alnitak, the ability to separate the domain from the host. Backup mail servers are, in the vast majority of cases, useless.

That I got the main purpose wrong I can accept, but backups are not at all useless. In the majority of cases, yes, they are useless.