Possible port 25 block and MX record issues

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zabory
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Possible port 25 block and MX record issues

Post by zabory » 2020-10-26 17:11

Greetings buckaroos!

First time ever using a forum but I need help so let me walk you through what I'm having issues with and give you (hopefully) all the information you need to tell me why I am a fool and what I did wrong.

Attached here
hmail diag results.PNG
is the diagnostic results from my hMailServer Administrator. As you can see, testing the MX record fails as well as testing the outbound port.

Lets talk about port 25 first.

My ISP (after waiting weeks for an email reply) says they do not block port 25. However, after some testing I believe they are 100% lying to me. Locally, I am able to connect to port 25 on my LAN (eliminating any firewall issues). However, any attempts to reach it through my domain name and public IP addresses are met with saddening results; as I cannot connect to the server. The way I tested this was making a simple socket connection in java using port 25. Since it does not work from both my public IP address and my domain name, I am ruling out a domain issue for this as well, leaving two things: My ISP and my Router. I have a netgear nighthawk router, who has port 25 forwarded to the computer I am hosting the server on (as well as 110, 143, and 587 so I can run the hMailServer). I do not believe it is a router issue. I would attach a photo of the port forwarding but you will just have to trust me that I did it correctly.

Lets talk MX record now. Attached here
MX record.PNG
MX record.PNG (2.14 KiB) Viewed 3969 times
is the MX record I currently have on my domain (zgamelogic.com). I believe I set this up correctly but it never hurts to have more eyes on it to see if its right. I have mail.zgamelogic.com pointing to my public IP address in an A record. I am assuming its throwing errors because it cannot connect to port 25 but I am sure you will let me know if I am wrong.

Okay! So, let me know what I did wrong and what I can do to fix my mistakes. If my ISP actually blocks port 25, what services or tools can I use to get around this?

Thanks for your time, I truly appreciate it!

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jim.bus
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Re: Possible port 25 block and MX record issues

Post by jim.bus » 2020-10-26 18:48

I did a couple simple tests on your mail.zgamelogic.com email server name.

I was able to Telnet to it on Port 110 but not on Port 25.

This tells me that your A-Record is set up properly.

Port 110 can be connected to on an inbound connection at least.

Port 25 cannot be connected to on an inbound connection at least as well.

Port 25 serves to purposes in email.
1. To send and receive email to/from other email servers.
2. To receive requests from an email client to send mail to other email servers. This means Port 25 should not be blocked for inbound connections.

Since Port 25 cannot be reached at all using Telnet it would seem 1 of 2 things may be happening.
1. ISP is blocking inbound and outbound connections on Port 25 which doesn't seem likely since Port 25 should be left open to inbound connections for email clients to connect with and most likely blocked only for outbound connections.
2. Perhaps your Router is not Forwarding correctly for Port 25 (still a Router Firewall issue) since you say you can connect from within your Local Network. But you didn't say how you confirmed you could connect to your email server from within your Local Network.

Virinum
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Re: Possible port 25 block and MX record issues

Post by Virinum » 2020-10-27 00:02

You’ve set up a mx record for mx.zgamelogic.com: https://mxtoolbox.com/SuperTool.aspx?ac ... elogic.com

That’s the reason why the mx record for zgamelogic.com couldn’t be found.

palinka
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Re: Possible port 25 block and MX record issues

Post by palinka » 2020-10-27 04:00

Virinum wrote:
2020-10-27 00:02
You’ve set up a mx record for mx.zgamelogic.com: https://mxtoolbox.com/SuperTool.aspx?ac ... elogic.com

That’s the reason why the mx record for zgamelogic.com couldn’t be found.
Yes. OP should change the mx record from mx.zgamelogic.com to zgamelogic.com, then point it to either mail.zgamelogic.com or zgamelogic.com (they both resolve to the same IP).

zabory
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Re: Possible port 25 block and MX record issues

Post by zabory » 2020-10-27 04:23

WOW
Fantastic! I fixed the MX record issue and now that is working. Unfortunately still no luck on the port 25 issue. Thanks for all who replied :D

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mattg
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Re: Possible port 25 block and MX record issues

Post by mattg » 2020-10-27 04:32

zabory wrote:
2020-10-26 17:11
Lets talk about port 25 first.

My ISP (after waiting weeks for an email reply) says they do not block port 25. However, after some testing I believe they are 100% lying to me. Locally, I am able to connect to port 25 on my LAN (eliminating any firewall issues)
jim.bus wrote:
2020-10-26 18:48
Since Port 25 cannot be reached at all using Telnet it would seem 1 of 2 things may be happening.
1. ISP is blocking inbound and outbound connections on Port 25 which doesn't seem likely since Port 25 should be left open to inbound connections for email clients to connect with and most likely blocked only for outbound connections.
2. Perhaps your Router is not Forwarding correctly for Port 25 (still a Router Firewall issue) since you say you can connect from within your Local Network. But you didn't say how you confirmed you could connect to your email server from within your Local Network.
My guess is that your ISP blocks port 25
Just 'cause I link to a page and say little else doesn't mean I am not being nice.
https://www.hmailserver.com/documentation

insomniac2k2
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Re: Possible port 25 block and MX record issues

Post by insomniac2k2 » 2020-11-03 01:40

It is almost uncommon for consumer grade ISP services not to block port 25. I can attest to this, because I recently left my employer and had to move my mail services to my home. Port 25 is blocked, so I was forced to use a service called Dynu. They have a Store/Forward service for $10 a year that allows you to set your mail MX record to them, and they will store/forward (or just forward if you choose) your email to you on a different port. It also pairs well with their free DDNS service which can update a first level domain name with a dynamic DNS record. AKA: If you own your own domain, it will keep your IP up to date.

Pretty slick for $10 a year.

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jim.bus
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Re: Possible port 25 block and MX record issues

Post by jim.bus » 2020-11-03 02:39

I don't know if it has something to do with ISPs in the US or what. But I am an AT&T ISP Residential Customer. up until a year or so ago, while AT&T implied Port 25 might be blocked, it wasn't because I had no trouble using hmailServer with them and with a DDNS hostname. However, about a year or so ago, I purchased Static IP Addresses from them Which I think they at least associate with Business Accounts though I do not have a Business Account with AT&T. Needless to say with the Static IP Addresses I definitely don't have a Port 25 Blocked issue. But I only went to Static IP Addresses because I wanted at least two IP Addresses and the Static IP Addresses were cheap enough ($15/month for a block of 5 usable Static IP Addresses). So AT&T is a major Consumer ISP and I've never had any issue with Port 25 being Blocked while using a Residential IP Address. I believe some ISPs such as Comcast are black listing all their Residential IP Addresses in the Black Listing Services or the Black Listing Services are just Black Listing all Residential IP Addresses. I heard what I considered a rumor to this affect.

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