Mail Server Name

So, if I understand correctly, the email is only sent 'internally' to the server itself?  Then the users download the mail from the server using the POP3?

If that is the case then you don't need to do anything with the ISP side.

If you need to send email out to the Internet then that is different.

To add to Chakko comments.
Currently what and how does your current ISP deal with your e-mail if at all.

Are your users just connecting via POP3 to pull down their mail to a Mail Client outside the network?

If this is the case what are they using (ip-address or public DNS  A record)?
If they are using a public record you will need to update your public NS with the new IP-Address that is associated with the public A record
example:  
Current record:  pop3.mydomain.com --> 67.45.250.3  
New ISP gives you 24.45.10.100  
New A Record: pop3.mydomain.com --> 24.45.10.100

If they are using ip-addresses then you will need to have the users manually change their POP3 profile.

To add to the other comments, since this particular question was not addressed,

Also the ISP is saying I will need a static IP for each domain I am hosting for reverse DNS. Is this true I didn't need it with the ISP I am currently using?

The only thing you really need reverse DNS records for are your outgoing (sending) mail servers.  Adding PTR records for anything else is really unnecessary.  It's not a bad thing to have one for any IP that you use however, it's better than not having a record at all.  However, as far as needing a static IP and/or reverse DNS for the sites you host, no you most certainly do not.

However, as far as needing a static IP and/or reverse DNS for the sites you host, no you most certainly do not.

Hmm could've has phrased that a little better.

However, as far as needing a static IP and/or reverse DNS record for each of the sites you host, no you most certainly do not.

To add to Patertrip comments

Do you own a domain name?  
If yes, is the new ISP hosting the domian as well as the DNS?  With regards to public DNS, do you have any public services that your company is hosting (web site, mail exchange, terminal services/citrix....etc) that will need pointers.

If no,  then you are set for what you need to give your ISP (nothing).

I host 4 sites for local schools. One of the things the schools can do is create a email and send it to their school families i.e. monthly newsletter.  They create the email through their web page and my server sends the email to the families. No one sends email back to the school nor does anyone at the school read emails from my server. I have outlook on my computer that has accounts created that reads any email that gets rejected. This computer is in the same domain as the server.

So there is nothing you need for your e-mail publicly, but you will need something for the Hosted schools.
That being said who will be hosting the Domain Name Registration and the Name Server?

I misread your original question, and after your last comment I see that you do indeed send mails from your server(s) to external accounts.

The sending IP(s) of your mail server(s) need to have matching A and PTR records.

You will need to update your SPF record for any sending domains to include the new IP(s) of your sending server(s).  If you don't currently have an SPF record, I highly recommend adding one.

When you send out email what is the address (and domain) that you send from.  Example when you send an email out is it from something like newsletter@school1.com ?   And does it change (the sender address) depending on what school it is?

Or is the sending address not related to the school's email domain name?

If the schools have their own domain names such as school1.com, school2.com, school3.com, school4.com
Then do you use any of those domain names in your sender address?

If yes, then you need to look at the DNS issues mentioned by the others and update for the appropriate domain name(s).

If your sending address is not related to any of the schoolx.com names then it is easier for you,  you only need to modify DNS for the domain name of your sender address.

SPF record and PTR (reverse DNS lookup) is required for Anti-Spam purposes.  Anti-Spam systems sometimes use those information to determine if you are sending out SPAM.  
Those records are not required for an email system, but it is recommended so that your emails don't get tagged or blocked by recipient Anti-Spam systems.

To be clear, you do not need to match A/PTR records of a sending server to match any domain that is in the the envelope for body From.  

You should, however, add an SPF record for each domain listing your sending server(s).

Each school does send emal with the from email address of their doman as newsletter@schoo1.com and newsletter@school2.com etc. So I think you are saying I need to change each A and PTR record for each domain. Is the A and PTR record on the DNS server?  In my case dyndns.com What do I put in the A and PTR record? Does this mean I don't need a static IP for each Domain I'm hosting?

You can have 1 IP for your mail server that sends mail for the 4 domains.  

I would use a STATIC IP address for the email server, you only need 1 IP.  If you are trying to use a Dynamic IP (from the ISP) then I would recommend you stop this route and look into an SMTP Relay service  (smtpauth.com   or authsmtp.com, DYNDNS has outbound Mailhop service, maybe that's the old name).  Then you would configure your mail server to use a 'Smart Host' / Relay server for email delivery.

the PTR record is made normally at your ISP DNS.  So you need to provide the info to your ISP and they will create the PTR record.

If you make SPF records, then you make a DNS TXT record type in each of your email domains.
www.openspf.org has info about making the SPF record and some links to tools to check the syntax and other stuff.
Basically, the SPF record is just a text string which has a list of mail servers (can be IP address or FQDN name, or some other options) which are valid servers for sending mail for the domain.  So your SPF records need to include any mail server that sends out mail for the school1.com domain.

You should give the mail server name to your ISP for making the PTR record.
If you telnet to port 25 of your mail server then you can see the SMTP response and see which name it is 'giving out'.  I would suggest you provide that name to the ISP

Open a DOS/Command prompt and enter this command:
telnet <your server name or IP address> 25

such as:   telnet 123.123.123.123  25

If your mail server SMTP banner shows some internal name then you can try to change that.
Or you can use a different name for your PTR record.  If you have a DNS host record for the server already, or you could create some DNS host record called  mail2.school1.com and use that.

When telenet to my ip address plus port 25 i get the folowing:
220 ctcg1.ctcg.online.server.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.4675 ready at Sat, 8 Oct 2011 10:21:07 -0400
 
If I look in control panel/system under Computer Name I see this

Full Computer Name ctcg1.ctcg.online.server.com
Domain ctcg.online.server.com

Do I give  ctcg1.ctcg.online.server.com to my ISP?
What do I then need to do with all the schools domans?

Thanks so much

Go into your IIS Manager and go to Properties of the SMTP Server.
Click on the Delivery Tab and then the Advanced button.  Then set the Fully Qualified Domain Name

You should make it match some DNS Host record.  

Example:  in DNS I can have a record called:  mail
so the server name is mail.school1.com
you should change the IIS setting to be:  mail.school1.com

I went in IIS Manager/Properties/Default SMTP Server.
Clicked on the Delivery Tab and then the Advanced button.  Then set the Fully Qualified Domain Name to Mail.

I'm not sure what else I have to do.

Thank You

You set it to mail.school1.com  (example), right?

You should contact your ISP and request the PTR record be made and give them the mail.school1.com (example) server name.

You can make the SPF records too now if you like.  1 records in each domain DNS.

The PTR and SPF stuff is not required to send out email.  It improves things and it is recommended for better email delivery.

I am guessing that you can already send email out?   This is just to answer the ISP and set things up with them?

Sorry I set the Fully Qualified Domain Name to just Mail. should I set it to mail.scool1.com?

Yes I can send email on my current ISP but I am moving to a new ISP and they want to know what my mail server is called so that I dn't get black listed.

Sorry I set the Fully Qualified Domain Name to just Mail. should I set it to mail.school1.com?

Yes I can send email on my current ISP but I am moving to a new ISP and they want to know what my mail server is called so that I dn't get black listed.

you should set it to the name you will use.  example:  mail.school1.com

You can do the telnet test to  verify that it is responding with the right name.

Then give the ISP the name (full name) and it should be OK.

But what about school2.com and school3.com

Is this what I shoud do to make sure the schools dont get black listed.
On my server set the mail server to mail.school1.com. Then go to dyndns.com and set the A record and PRT record for each schools domain to mail.school1.com or do I have to have a IP address for each schools doman?

Just make sure that whatever hostname your Exchange server is setup to use for outgoing mail has a matching A and PTR record, and that you have an SPF record setup for your domain which includes the IP(s) of your sending server(s).  It does not matter what that hostname is, as long as it can resolve forwards and backwards and the records match.

My earlier replies to this question which apply to your last comment:

http:#36931926
http:#36934744

Make the settings in DynDNS for the A record mail.school1.com.  The ISP makes the PTR record in their DNS.

Also, setup the SPF record in each domain (school1.com school2.com school3.com school4.com).

You only need to setup the PTR record for mail.school1.com   (this should be for the IP address that you set mail1.school.com on)
You can setup A records also in the other domains if you like (e.g.:  mail.school2.com, mail.school3.com mail.school4.com)  they can all point to 1 IP address

Ok just to make sure I have this correct I do the following:

In my server I name the mail server mail.school1.com

I tell my ISP that my mail server is mail.school1.com

In dyndns.com for school1.com I set the A record to my IP address (i tried making the A record  mail.school1.com but it would only allow an IP address so I made it my statc IP Address)

In dyndns.com for school2.com I set the A record to my IP address and I do this for schools 3 and 4.

I ask my ISP to create a SPF record for school1.com, school2.com, school3.com and school4.com

Is this correct and all I have to do?

Thanks

I added mail for each school in dyndns.com and it did create a A record with mail.school1.com with my IP address

I can't add SPF records in dyndns.com the only records I can add are:
A, AAAA, CNAME, LOC, MX, NS, PTR, SRV, TXT

Thanks

SPF records are TXT

Ok Thanks a lot I think I got it