MX Records and Dynamic IP

[kitkat22]

Hey guys,
I want to setup a small email server at home for family. I already have the server up and running and everything works great except for SMTP. I have a domain that I'm trying to route to my dynamic IP address. I use DynDNS already for my webpage and ftp server, but getting SMTP to work with this setup has really been frustrating me. DynDNS requires a fully qualified domain name in the MX records, but how do I do that if I have a dynamic IP?

 

[JackMDS]

You need an email server on the Internet, right now it is your ISP.

Take a look at your account at DynDNS they offer such service.

 

[Tbirdkid]

meh, thinking out loud here. since its a dynamic ip, that doesnt really matter because the ip handed to you should be resolved by the isp. just set up the router/switch to statically set your servers ip. after thats done, then set up exchange as the mx record holder and the smtp should work. the fqdn will hold the mail rights, so their email address will have to end in @yourfqdn.whatever

the dynamic ip shouldnt really matter as long as your provider dyndns can handle that.

 

[JackMDS]

If (as an example) One has a DNS service with domain like jack.dyndns.com and expect to run an email server using an email address like jack@jack.dyndns.com it is impossible to do so with special arrangement with the DNS service.

Your ISP email server would not resolve email that is not of the ISP's domain.

 

[drebo]

You guys are over-thinking this.

Just set the MX record on your domain to be the same as your DynDNS domain. That's all you need to do. I.E. if your domain is whatever.com and your DynDNS domain (automatically updated, of course) is whatever.dyndns.com, then just set the MX record of whatever.com to be whatever.dyndns.com. This does, of course, assume that DynDNS will allow you to specify an MX record, which I believe they do.

Other problems you will likely run into: many ISPs (Charter, for one) do not accept mail from dynamic IP addresses; many ISPs (AOL and Yahoo) do not accept mail when the reverse lookup does not match your mail server's A record (I.E. when you do an nslookup on your IP address, it needs to come back as whatever.dyndns.com) and this is impossible to correct with a dynamic IP address; SPF records will be impossible to maintain; and, most importantly, it's more than likely against your ISPs ToS and they will block outgoing port 25 access.

Over all, it's not worth the headache. Check out Google Apps Messaging: http://www.google.com/apps/int...business/editions.html . It'll just be easier.

 

[mxnerd]

IIRC, I did setup a subdoamin email server longtime ago using NO-IP.com

Afriad DNS is another DDNS service I believe support subdomain email. I never tried it though.

http://freedns.afraid.org/

 

[RebateMonger]

Originally posted by: drebo
Other problems you will likely run into: many ISPs (Charter, for one) do not accept mail from dynamic IP addresses; many ISPs (AOL and Yahoo) do not accept mail when the reverse lookup does not match your mail server's A record (I.E. when you do an nslookup on your IP address, it needs to come back as whatever.dyndns.com) and this is impossible to correct with a dynamic IP address; SPF records will be impossible to maintain; and, most importantly, it's more than likely against your ISPs ToS and they will block outgoing port 25 access.

Yeah. If you can't afford or can't get a "business Internet account" with a static IP address, there's lots of potential pitfalls in hosting a mail server.

One thing that can help is to user your ISP's mail server as a "smart host" (if the ISP offers it). Outgoing mail is sent to the ISP's mailserver, which then relays mail to the final recipient. The outgoing mail then is coming from the ISP's server, which is generally "trusted" and not blocked by other mailservers.

 

[Tbirdkid]

read this, especially the part about needing a static ip.

http://mxtoolbox.com/cs/forums/thread/11766.aspx

find a static ip. the other notion is to have your exchange hosted. someone else besides you will need to hold the mx record because you do not have a static ip. to clarify, if your ip address keeps changing, the domain name will get blacklisted and alot of your emails will be going straight to the trash/junk/spam folders of peoples email boxes.

if you do get a static, i would still use someone else to filter the email or you will get hammered. i like appriver. not a fanboy, but i like them for their message filtering. good luck!

 

[JackMDS]

Originally posted by: Tbirdkid
read this, especially the part about needing a static ip

This is very true.

A partial solution is to maintain a free dynamic IP, and pay a small fee to the DNS service to provide email mx record service.

They would reflect their static IP to the Internet and redirect the mail to the member's current Dynamic IP.

Most of the DNS services provide this option.

 

[kitkat22]

Thank you guys so much for the responses. The responses were excellent and I learned a bit more from them. I decided to take the google apps pathway and I actually already have it setup. I'll have to wait for more money before I go static IP. Ah well, life moves on

 

[Tbirdkid]

great move.

 

[sonoma1993]

Originally posted by: drebo
You guys are over-thinking this.

Just set the MX record on your domain to be the same as your DynDNS domain. That's all you need to do. I.E. if your domain is whatever.com and your DynDNS domain (automatically updated, of course) is whatever.dyndns.com, then just set the MX record of whatever.com to be whatever.dyndns.com. This does, of course, assume that DynDNS will allow you to specify an MX record, which I believe they do.

Other problems you will likely run into: many ISPs (Charter, for one) do not accept mail from dynamic IP addresses; many ISPs (AOL and Yahoo) do not accept mail when the reverse lookup does not match your mail server's A record (I.E. when you do an nslookup on your IP address, it needs to come back as whatever.dyndns.com) and this is impossible to correct with a dynamic IP address; SPF records will be impossible to maintain; and, most importantly, it's more than likely against your ISPs ToS and they will block outgoing port 25 access.

Over all, it's not worth the headache. Check out Google Apps Messaging: http://www.google.com/apps/int...business/editions.html . It'll just be easier.

that pretty much how I have my email/mx record setup. I have mx record and domain name hosted through yahoo. Configure it to point to my dyndns.org address. and made some other configurations. After a few hours of tweaking my server and mx records, and testing. My home email server is able to send/received email on my dynamic IP. Been working great for the past 10months

 

[Crusty]

Originally posted by: cscpianoman
Thank you guys so much for the responses. The responses were excellent and I learned a bit more from them. I decided to take the google apps pathway and I actually already have it setup. I'll have to wait for more money before I go static IP. Ah well, life moves on

Google apps is great, I use it for all the websites I host for myself and friends. Even though I have a VPS, running a full blown secure MTA and client access for e-mail takes up too much resources so it's just far easier to use Google apps.

 

[hiromizu]

You're just going to get blackfisted. Not a great move.