# Does using dynamic IP cause much trouble for web server + DNS &  E-Mail MTA



## aurora (Dec 2, 2009)

Hello,  

Though not specific to FreeBSD or any other OS but I've been setting up my own web server (on FreeBSD 7.2) and now have plans to set up my own DNS server (BIND) and an E-Mail MTA (sendmail) but I started to feel that using dynamic IP would cause some trouble in the operations of DNS server and E-Mail MTA.

Web server is no problem with Dynamic IP because I can easily connect to a free Dynamic DNS service and it instantly records my dynamically changing IP, but I'm not sure about the DNS and E-Mail MTA case.

I wait for your suggestions and comments on this issue.

Thanks.


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## aragon (Dec 2, 2009)

A DNS server on a dynamic IP is a definite no no.  An e-mail server could work with the help of dynamic DNS and an upstream relay, but not ideal...


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## Voltar (Dec 2, 2009)

A DNS and MTA are both no no's on a dynamic connection. A dynamic IP on a mail server could cause issues with your outgoing email being rejected, flagged as spam or black-holed because most dynamic IPs are on blacklists. Also, some providers block necessary ports. 

As for a DNS server, if it is going to be authoritative you'll have to update the IP each time it changes for the nameserver registration at your domain's registrar.


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## vivek (Dec 2, 2009)

Only web server will work and all other will fail.


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## dclau (Dec 2, 2009)

aurora72 said:
			
		

> ...
> Web server is no problem with Dynamic IP because I can easily connect to a free Dynamic DNS service and it instantly records my dynamically changing IP, but I'm not sure about the DNS and E-Mail MTA case
> ...



I think afraid.org's services will be just fine for the DNS part, for the E-Mail why not giving Google Apps a chance? For a small domain should be enough


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## aurora (Dec 2, 2009)

Thank you for the valuable suggestions. You're right about the suitableness of a static IP, I agree. However,

Here a commenter claims that he uses a DNS server on an IP which doesn't change very often (i.e. a dynamic IP?) Quote: I've done this with Comcast in San Francisco. My IP doesn't change very often, so I've been able to get away with running my own DNS as well.

The reason I 'm interested in running a DNS Server is the wish to run my own MTA. I'm not sure if a self-DNS server is absolutely required to run an MTA but it seems so. 

And just in case you may wonder, the reason I want all this on a dynamic IP is that I wish to be independent of ISP and the related ties. I plan to install all of the server software on a small computer and if needs arise, I may have to change my location carrying it along. And it would be very suitable to be IP-independent (and ISP dependent, even connection technology independent; I might choose to connect my server someday via 3G, perhaps)

You might say what I'm talking about is an IP which doesn't change "very often". It's only that when the IP changes, things must not be hard to adjust.


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## Pushrod (Dec 2, 2009)

Running your own DNS server with a dynamic IP is going to cause problems. You will need to keep an eye on it all the time and update your NS records for the domain each time it changes.

My IP changes every 6 months, which is not all that often, but you'd need to be prepared to deal with downtime every time it changes.

If you really want "ISP independence" run the server on a network that really is independent of the ISP.

As another poster pointed out, if you can even run a mail server (as in, your isp doesn't block port 25) you are likely going to be on every spam blacklist on earth.


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## aragon (Dec 2, 2009)

aurora72 said:
			
		

> The reason I 'm interested in running a DNS Server is the wish to run my own MTA. I'm not sure if a self-DNS server is absolutely required to run an MTA but it seems so.


Not true.  What makes you think that?



			
				Pushrod said:
			
		

> If you really want "ISP independence" run the server on a network that really is independent of the ISP.


I agree.  All you need is a small VPS from, say, JoinVPS - $6/month.



			
				Pushrod said:
			
		

> As another poster pointed out, if you can even run a mail server (as in, your isp doesn't block port 25) you are likely going to be on every spam blacklist on earth.


Yes.  This is why I suggested using an upstream relay, most likely the access ISP's relay.  Mail servers on dynamic IPs work pretty well provided the MTA is configured to relay outgoing mail appropriately.


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## DutchDaemon (Dec 2, 2009)

Having a stub resolver/cacher on the MTA will speed things up a little bit, but there's no need to actually _be_ a DNS server yourself.


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## aurora (Dec 2, 2009)

Thank you again for the valuable feedback.



			
				aragon said:
			
		

> Not true.  What makes you think that?


In the documentations of QMail, there 's a whole chapter called "How to run a DNS server" which explains publishing mail server adresses, etc. And also in sendmail tutorials there are constant mentions about DNS settings, which seem to suggest that running a DNS server makes things easier. 

But of course it's better if I don't have to run a DNS server in order just to run MTA.

I might subscribe to static IP of my ISP (which is "ttnet", the greatest ISP of TÃ¼rkiye) ttnet normally does not block any port related to web serving, such as 80 or any other specific port but it does try to replace the SMTP port 25 in favor of 587, eg I currently use 587 for my personal E-Mail account. 

It seems I'll have to use the static IP service, which doesn't cost too much (about $2/month), in order to run a reliable web & e-mail serving.


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