Do eircom block port 25

Mickser_52

Hi,
Can anyone tell me does Eircom.net block port 25 for residential customers.

I have been trying to set up an email server on an old imac, i have portforwarded port 25 and enabled it on my firewall but nothing seems to be able to get through?

cpu-dude

Course they don't, that's for Outgoing mail via POP3. What broadband provider are you using because your Outgoing Mail Server (SMTP) has to be the one of your ISP.

Mickser_52

i'm a little confused with this reply when i went to custom services on the netopia router page, smtp was tcp port 25 and pop3 was port 110.

i am an eircom broadband customer

cpu-dude

The don't even need to be opened in the Netopia router, they always work. You haven't described what exactly happens when you try send / recieve a mail.

Mickser_52

I am not having any problem is i use the standard mail program such as mac mail or thunderbird.

I have set up a web server with a host name from dyndns.org e.g. example.dyndns.org.

I would like to use an email address such as admin@example.dyndns.org and I have managed to send emails using a php script which i can open with a standard mail program but when i send a test reply it appears to send but never seems to arrive.

NullZer0

cpu-dude wrote: »

Course they don't, that's for Outgoing mail via POP3. What broadband provider are you using because your Outgoing Mail Server (SMTP) has to be the one of your ISP.

Eircom don't block it but a number of ISP's do.

Mickser_52

thanks for that. The solution to my problem must lie elsewhere

NullZer0

Mickser_52 wrote: »

thanks for that. The solution to my problem must lie elsewhere

Send or receive mails on that address?

If you wanted to receive you need an MX Record configured.
http://en.wikipedia.org/wiki/MX_record

ronkmonster

you need to modify the mx record of the domain to point to ip of the email server.

what mail server program are you using?

Mickser_52

I am trying to configure postfix but it does not seem to be listening on port 25 someone suggested that eircom might be blocking port 25 as some isps are doing

ronkmonster

have you pointed your domains mx record to the servers ip?

you should be able to test if port 25 is open by using telnet to connect to your server

connect to server ip with telnet on port 21. if it works it should give a welcome message (if configured)

Mickser_52

not too clear about mx records and dynamic dns

can telnet localhost on port 25 but when i try from remote computer get a message saying that connection is being actively refused. have portforwarded port 25 and set firelwall to allow it

got a connection on port 21

ronkmonster

are you using a static ip or dynamic (does it change or always the same)

if it changes i don't think it will work (may be wrong here)
you'd have to keep changing mx records to new ip

and dns changes take time to spread

mukki

whats the advantage of running an email server? Over a simple gmail

Mickser_52

are you familiar with dyndns.org it gives you a domain name and actively changes your ipaddress when the isp changes it. Your domain name always has the upto date ip address.
This could be a possible cause of difficulties.

ronkmonster

if you do a mx record scan does it match your current ip?

this should tell you
http://www.blacknight.com/dns/

johnciall

Irrellevant of the multitude of problems you'll run into running a mailserver on a resi connection you won't be able to set up a PTR record for the IP address and as such a lot of mail servers won't accept inbound mail from your server



try telnetting to eircoms SMTP server from your local machine on port 25 if you get connected it means the port is open and you need to start looking at your internal config


out of interest what isp's block port 25?

Mickser_52

when i enter "user".dyndns.org some of service providers give my ip address
but give my mx as X dydns.org

ronkmonster

well the mx can be a name rather than ip.
you'd need to check with the provider to see how they handle emails

Mickser_52

ok then thanks that test site will be useful. I have made some progress in configuring postfix but it is slow going.

Gadgetman496

johnciall wrote: »

out of interest what isp's block port 25?

Well I know Smart do for sure & I believe a lot of others do too.

I don't fully understand how that effects users though? I'm with Smart & can send & receive mail on POP3 without problem using the likes of Outlook Express & Outlook with the ports set to 25, so is it only mail servers that it effects or what?

-

NullZer0

You can use dyndns.org mx service. Worth looking into

Mickser_52

I set an mx record with dyndns.org and then tried mxtoolbox.com and found my mx record and also that i am blacklisted with some sites. How could that happen? I don't know.

Gavin

DSL client ip ranges might be blocked as typically the only people running email servers on those ranges are those that have been infected with some sort of virus/worm and are spreading spam.

If you can telnet to port 21 on your machine from an external IP, but not port 25, (with the same configuration on your router/firewall) then 25 is being blocked.

NullZer0

Is this a Unix box? Have you got PHP/sendmail installed?

Mickser_52

I have sorted everything out with help from the forum on dyndns.org.
Eircom are not blocking port 25 as I am now able to send and receive on my mail server. The problem was that I had not configured Postfix Main.cf and Master.cf files correctly.

I do not need to have an mx record set.

In relation to blacklist I found the following on the Spamhaus website:

[What if I want to run a mail server on dynamic IPs listed in the PBL?
Due to the vast volumes of compromised PCs spewing spam "direct-to-mx" from dynamic domestic Internet connections, most major mail systems choose not to accept unauthenticated SMTP mail from servers on dynamic IPs.

Unless you use Authenticated SMTP, there is no way for a machine to differentiate between legitimate email sent by your server from a dynamic IP and spam mail sent by a virus on a dynamic IP next door to yours. Most networks therefore nowadays make it their policy not to accept unauthenticated SMTP email sent "direct-to-mx" from dynamic IP pools. The Spamhaus PBL enables networks to enforce this policy.

If you're on a dynamic IP address and you absolutely need to run your own mail server, then use your ISP's outgoing mail relay as a 'smarthost'. If your ISP does not provide an outgoing mail relay, find a commercial smarthost provider. Such smarthosting arrangements are very common and inexpensive; contact your ISP or a hosting company for information.

Industry best practice is to block outgoing port 25 of dynamic pools (MAAWG documents).]

Thankfully this does not include Eircom as yet.