Can I unblock Port 25 on Spark MBB?

Forums › Spark New Zealand (including Skinny and BigPipe) › Can I unblock Port 25 on Spark MBB?

timbosan

2159 posts

Uber Geek

#171439 18-Apr-2015 09:39

Hey all,

I just moved out of my place where I had VDSL, and run my own Exchange server (part of SBS2011). I am currently using a Spark 3G MBB t-stick (in the back of my VDSL modem), which works great for everything except receiving email in Exchange due to Port 25 being blocked.

Is there anyway to unblock this on MBB?

Or is there any other solution to receiving email in Exchange on a mobile data connection as a work around?

I get "SMTP Connect - Failed to Connect" from MXToolbox:

http://mxtoolbox.com/SuperTool.aspx?action=mx%3ablackknightcoders.com&run=toolpage

1 | 2

6231 posts

Uber Geek

Trusted

Lifetime subscriber

#1286707 18-Apr-2015 09:48

It will be a NAT'd connection for starters, unless they have "direct" APN or something you can use.

Rural IT and Broadband support.

Broadband troubleshooting and master filter installs.
Starlink installer - one month free: https://www.starlink.com/?referral=RC-32845-88860-71
Wi-Fi and networking
Cel-Fi supply and installer - boost your mobile phone coverage legally

Need help in Auckland, Waikato or BoP? Click my email button, or email me direct: [my user name] at geekzonemail dot com

Jase2985

13457 posts

Uber Geek

ID Verified

Lifetime subscriber

#1286710 18-Apr-2015 09:55

http://www.spark.co.nz/help/internet-email/plans-services/port-25.html

timbosan

2159 posts

Uber Geek

#1286731 18-Apr-2015 11:05

Yeah I read the Port 25 page, and was going to ring them, but that would (I thought) only be for fixed line broadband.

Is there a service for email DELIVERY in the same way as I use SMTP2GO for email SENDING that allows me to use my Exchange Server on a mobile data connection? I had a look but couldn't find anything specific.

Coffeebaron, I don't suppose you know of any direct APN's? Damn shame a Master Splitter cannot help here!

nitrotech

1285 posts

Uber Geek

#1286751 18-Apr-2015 11:38

direct.telecom.co.nz is(was) the one that gives you a public IP - haven't used it in ages so don't know if it's still active but it's unlikely to have unblocked port 25.

You could have the mail delivered to standard POP mailboxes then use exchange's pop3 connector to gather the email say every 10 mins.

sbiddle

30853 posts

Uber Geek

Retired Mod

Trusted

Biddle Corp

Lifetime subscriber

#1286847 18-Apr-2015 15:42

Quite simply there isn't really a way to make this work.

You get a NAT IP rather than a public IP for a start, and even if you use an APN giving a public IP I believe every Telecom APN is still firewalled against uninitiated inbound traffic traffic. Even if they do offer an APN that does allow it you're up against the issue your IP address will continually change.

Talkiet

4792 posts

Uber Geek

Trusted

#1286864 18-Apr-2015 16:19

Sorry, I'm NOT in the mobile space and I can't be a lot more help than the helpdesk at this stage, BUT... The direct APN I believe is not firewalled off against uninitiated inbound traffic. Happy to be corrected, and there may well be a specific port 25 block on them, but it's worth a go.

For everyone else though.... Simply DON'T use the direct APN. It's a bad idea ~100% of the time.

For the avoidance of doubt - if you use the direct APN and get a public IP, and map services to it (like email), you are opening a potential channel for significant costs... Based on your posts I think you know this already but for everyone else, DON'T use the direct apn.

Cheers - N

ps. Oh yeah, I also have no idea about the persistence of IP addresses on mobile, or if statics are even possible.

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

coffeebaron

6231 posts

Uber Geek

Trusted

Lifetime subscriber

#1286881 18-Apr-2015 16:47

Is this MBB connection just a temporary thing? RBI Wireless could be another option.

Rural IT and Broadband support.

Need help in Auckland, Waikato or BoP? Click my email button, or email me direct: [my user name] at geekzonemail dot com

Equinox IT

Cloud spending continues to surge globally, but most organisations haven’t made the changes necessary to maximise the value and cost-efficiency benefits of their cloud investments. Download the whitepaper From Overspend to Advantage now.

timbosan

2159 posts

Uber Geek

#1286885 18-Apr-2015 17:06

Coffeebaron - this is temporary, just whilst we are looking for a new house. It is simply so I can get my email - I have access to free WiFi but the thought of trying to use Exchange over that was just too terrifying!

Talkiet - I don't this this matters. Same as the NAT issues raised earlier by Coffeebaron. I have simply copied the IP address from the modem (the 3G part that is) and changed my domain name to that. Everything is working fine, even remote access to the server (its SBS2011) and webmail works, even receiving (as I use SMTP2GO). Its only SENDING email that wont work due to the Port 25 block.

But I think I have a work around - has anybody heard of http://ghettosmtp.com? They take mail on port 25 to their own servers, then push it out again on another port, which when setup in Exchange on the mail server should get around the port 25 blocks. And from what Talkiet says, it will be a LOT more secure than the direct APN.

yitz

2074 posts

Uber Geek

#1286948 18-Apr-2015 19:35

timbosan:[..] webmail works, even receiving (as I use SMTP2GO). Its only SENDING email that wont work due to the Port 25 block.

Surely SMTP2GO is for sending and not receiving? Last time I used SMTP2GO they provided access on port 80 and this was used to overcome issues with domestic ISP filtering of port 25.

timbosan

2159 posts

Uber Geek

#1286953 18-Apr-2015 20:02

yitz:
timbosan:[..] webmail works, even receiving (as I use SMTP2GO). Its only SENDING email that wont work due to the Port 25 block.
Surely SMTP2GO is for sending and not receiving? Last time I used SMTP2GO they provided access on port 80 and this was used to overcome issues with domestic ISP filtering of port 25.

Whoops! I got these the wrong way around! Yes, SMTP2GO is for sending, which is probably why it works 100%. Receiving has always been done directly in Exchange, and has always worked well. I can send fine, and have checked that 100% of the time. I cannot receive any mail.

sbiddle

30853 posts

Uber Geek

Retired Mod

Trusted

Biddle Corp

Lifetime subscriber

#1286956 18-Apr-2015 20:07

I'm still not sure how you're going to receive mail even if you overcome APN and firewall issues, your IP will keep changing continually.

SirHumphreyAppleby

2844 posts

Uber Geek

#1287026 18-Apr-2015 22:07

timbosan: Or is there any other solution to receiving email in Exchange on a mobile data connection as a work around?

Something to consider...

Get a cheap VPS, which will cost you about $US3 per year, running any Linux or BSD flavour you like, and OpenSSH (almost certainly enabled by default). On your Exchange box, run PuTTY using the -R option, to forward the remote port 25 from the remote host to your local machine (port 25). Update the MX record for your domain to point to the IP of the VPS.

You would probably want to investigate tools which run plink (the command line version of PuTTY) in the background and automatically restart the connection if it goes down. I used to have such a tool, but I've forgotten the name.

Note also that this will cause the SMTP connection IP to be presented as the IP of your Exchange server, so you would lose any ability to block by IP.

A similar configuration can be used for sending, although more complex to set up, and is potentially problematic given many cheap VPS providers have IP ranges used by spammers.

timbosan

2159 posts

Uber Geek

#1287032 18-Apr-2015 22:14

sbiddle:

I'm still not sure how you're going to receive mail even if you overcome APN and firewall issues, your IP will keep changing continually.

That's what I thought, but it's mean constant for 48 hours. Even if it changed every few days, it doesn't matter as I hope to be back on DSL within a week.

However it is an interesting exercise - I would have liked to be able to have this set up running for just email, and use up the credit I have on the SIM.

How often would you have expected it to change sbiddle?

timbosan

2159 posts

Uber Geek

#1287034 18-Apr-2015 22:18

SirHumphreyAppleby:
timbosan: Or is there any other solution to receiving email in Exchange on a mobile data connection as a work around?

Something to consider...

Get a cheap VPS, which will cost you about $US3 per year, running any Linux or BSD flavour you like, and OpenSSH (almost certainly enabled by default). On your Exchange box, run PuTTY using the -R option, to forward the remote port 25 from the remote host to your local machine (port 25). Update the MX record for your domain to point to the IP of the VPS.

You would probably want to investigate tools which run plink (the command line version of PuTTY) in the background and automatically restart the connection if it goes down. I used to have such a tool, but I've forgotten the name.

Note also that this will cause the SMTP connection IP to be presented as the IP of your Exchange server, so you would lose any ability to block by IP.

A similar configuration can be used for sending, although more complex to set up, and is potentially problematic given many cheap VPS providers have IP ranges used by spammers.

But wouldn't that still be blocked as its still transferring to the Exchange server over Port 25?

SirHumphreyAppleby

2844 posts

Uber Geek

#1287035 18-Apr-2015 22:21

timbosan: But wouldn't that still be blocked as its still transferring to the Exchange server over Port 25?

No, because over the mobile network, you're establishing an outbound SSH connection on port 22, not trying to receive a connection on port 25.

1 | 2