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19

As long as the system pointed at by the MX record has an A record itself, then yes. For example: example.com can have a MX record pointing at mail.otherdomain.com. As long as the name mail.otherdomain.com itself is resolvable to an IP address, this is a valid configuration for example.com. Strictly speaking, mail.otherdomain.com should be an A record with ...


19

Yes, it would be possible, but you will lose some important advantages if you choose to do so: If you point all services to the same DNS name, you can't put them onto separate servers any more without reconfiguring any client that refers to them. As an example: With different names, when the load on the server grows too much, you can simply offload the ...


18

If you set up a name for this server, like mail.example.com. IN A 1.1.1.1 then you set up a MX server like example.com. IN MX 10 mail.example.com.


17

Hotmail fails to use proper DNS rules. Hotmail will always try to deliver to the domain's A-record first and will ignore MX-records. If the domain A-record accepts a connection (eg. it runs a mailserver) it will try to deliver the email, which in most cases will not be an issue if the webserver and mail server are the same box. However, if an domain uses a ...


15

it used to be the case that having a backup MX was a Good Thing. the internet was unreliable, email was unreliable, smtp was not so common, bang-path addressing and other forms of manually-specified mail routing was common, and uucp was the mail protocol of choice. That was a long, long time ago. It's not true today. sending MTAs will queue up ...


15

According to RFC 1123, the MX record cannot point to a CNAME. If I were in your situation, I would setup mail.ourdomain.com as an A record pointing to the new suppliers IP address and then quickly work on changing all MX records over to the correct data. Then address why changing MX records is so difficult in your organization. That being said, most mail ...


15

This is a common error. You cannot use a CNAME RR for your root domain (e.g. company.com) and define additional resource records for the same zone. See Why can't I create a CNAME record for the root record? and RFC1034 section 3.6.2 for details: If a CNAME RR is present at a node, no other data should be present; this ensures that the data for a ...


14

MX records were invented for precisely this application: allowing mail for a specific host to be handled by another host. The first thing to point out is that MX records do not contain IP addresses, they container a pointer to a hostname. So for your example you would have something like: abc.tv. A a.a.a.a MX 5 mail.abc.tv. ...


14

Just use a telnet session to test email delivery. As an example, # telnet host.domain 25 Trying host.domain... Connected to host.domain. Escape character is '^]'. 220 ESMTP HELO example.com 250 MAIL FROM:user@example.com 250 ok RCPT TO:user2@example.com 250 ok DATA To: user2@example.com From: user@example.com Subject: test message Test message body. . ...


13

Do yourself a favor and set them up with a gateway anti-spam service such as Postini. For a few dollars per mailbox per month, there's absolutely no reason not to and you'll not only eliminate 99% of your spam, you'll also enjoy having access to their spool service (handy for scheduled or unscheduled downtime), not to mention the bandwidth savings by ...


12

You will need to correct the MX records in your DNS which is probably hosted on your server at Rackspace. You can locate the MX records you need in the Email Control Center. Here is a guide to do so: http://support.godaddy.com/help/article/5444


11

Put periods on the ends of the MX records. (Forceds them to be FQDN instead of relative).


11

Yes, an MX record is there only for incoming mail.


10

Unfortunately, what you're running into is a limitation of the DNS specification. Having an MX record for the same hostname as is defined as a CNAME record will fail in most DNS server implementations. Some older DNS servers will allow this, but they have been mostly phased out in favor of newer, more secure implementations. Instead of using CNAME ...


10

I've tried this, and I can strongly recommend that you DON'T DO IT! It seemed like a good idea at the time, but after mail from various senders starting disappearing, I realized that it was a mistake. What I didn't realize was that there are lots of terribly written SMTP servers out there, that don't follow the spec and are fairly retarded about handling ...


10

It's an RFC violation to use a CNAME as an MX record. From RFC2181 section 10.3: The domain name used as [...] part of the value of a MX resource record must not be an alias. [...] It can also have other RRs, but never a CNAME RR. In practice it will often work, but some MTAs are aware that you shouldn't do it, so assume they can ignore you or ...


10

http://whoisrequest.org/history/ This one is really cool . No registration needed .


9

A word of warning: An MX record provides information about where email should be delivered. It does not necessarily provide any information about where email originates. It is entirely possible -- even likely -- that mail will be coming from a system that is not listed as an MX for the given domain. SPF records, on the other hand, allow you to verify ...


9

An MX record must be a name, not an IP. That means the host pointed to by an MX record for your domain must itself be directly resolvable to an A record. However there is no requirement for that A to be part of your domain. For example you can have Google Apps handle the MX records for your domain, while you manage the A records for the domain and www.


9

Definitely a NO, not with a 127.0.0.0 IP.The entire 127.0.0.0 range on IPv4 works as loopback addresses, thus when any machine connects to IPs in that range it will try to connect to itself. Your MX record IP address should be accessible from the outside world and what that result is telling any server doing a MX query, to try to connect to itself. If my ...


8

You can't use a CNAME record at the zone apex. This is because a CNAME record defines one name to be an alias of another regardless the requested record type. This, in turn, also means that a CNAME record cannot coexist with other records as that would be a conflict/inconsistency. The zone apex always has at least SOA and NS records, which means there can ...


8

After a lot of work and research here, I have found an acceptable solution. First, it is important that we all follow the RFCs. I patched my DNS server to violate the RFC, and I discovered that several other major DNS servers would not respect the change. The appropriate move is to put the MX on the host that the CNAME points to. So, if ...


8

Make sure that mail server MX record is referring has A record, CNAME is not enough. This is important but I do no remember why. Here is an example: $ORIGIN example.com. @ IN SOA dns0.yourisp.com. zone.yourisp.com. 1308717736 21600 7200 1209600 10800 @ IN NS dns1.yourisp.com. @ IN NS dns2.yourisp.com. @ IN MX 10 ...


8

No spf records are NOT required if your domain doesn't send emails however for benefit of reducing the risk of spam mail coming from that domain setting the spf record of "v=spf1 -all" is good so that spf checking servers see this and automatically reject email from that domain


8

You don't strictly need to publish any SPF records at all, it is a voluntary system. That said, if you do publish an SPF record, you can: Help the Internet at large a tiny, tiny bit because it gives spammers one less domain to spoof. (Marginal benefit, but...) Help preserve your domains 'reputation' by making it less likely to be spoofed in spam. ...


8

http://www.pcmech.com/article/the-mysterious-1e100-net/ What is 1e100.net? It’s Google. A WHOIS lookup for that domain reveals it’s owned by them. Why would Google use an "weird" domain name like 1e100.net? It’s symbolic of a googol (10×10^100) which is where Google gets its name from.


8

You usually want to receive mail for address@mydomain.com, not for address@mail.mydomain.com, so an MX entry for mydomain.com will be sufficient, which usually should point to mail.mydomain.com to enable your mail server as an MX.


7

http://dnshistory.org/ Seems to have a patchy history, all for free.


7

I can vouch for #2 (reverse PTR) being important, but not #4 (mail server domain matching "from"). We set up mail servers all the time, and most mail hosts don't really even care about #2. The main thorn is always AOL, and they list standards you can check off.


7

There's no way you can do this via the MX records within a single domain name--DNS is always going to point emails destined to alice@acme.com and bob@acme.com to the server that answers at the highest-priority MX record. (In other words, the second -highest priority MX record is not used unless there was no response at the first IP address. If you connect to ...



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