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76 posts

Master Geek
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Topic # 128947 29-Aug-2013 11:41
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I switched from ADSL2 to VDSL around noon yesterday, a 2 minute job as I already master spitter in place, I'm 500m from the cabinet, VDSL modem already configured, just needed Telecom to switch over at their end really. I have a static IP address as I have my own server for routing, hosting email, http etc. After their tech was on the phone for 30 minutes arranging the switch over, all seemed good with 40Mb/12Mb down/up. However after switching to VDSL, it appeared that inbound (but not outbourd) port 25 was blocked by Telecom (I wasn't getting external emails). I have port 587 in use too, but it appeared that wasn't being used. So I could send email, but nothing external was arriving. I'm still using smtp.xtra.co.nz, as I don't think send.xtra.co.nz works for me (because I would need to authenticate lots of email addresses).

Of course I fluffed around with all the modem settings first trying to see if I was doing something wrong, as that was really the only thing that had changed. After an hour or so of that I called the beloved Telecom Broadband Helpdesk

They suggested all the usual irrelevant rubbish, which in my experience you have to just politely point out is irrelevant rubbish before you can get escalated, things like resetting my modem to the factory defaults, turning off my firewall (the modem is in bridge mode connected to an Ubuntu server running iptables and postfix), or powering it off and on (computer and modem, with the classic leave it off for 10 minutes in between suggestion), or using webmail to access my email (no, they really didn't get my setup). The real rub was the first time I called (at about 2pm) they insisted they couldn't do anything until after 7pm when the install ticket closed, with a dim hope that because everything is not finished until that time, so it might come right before then. When I called back at 7pm I eventually got escalated all the way to level 2 (woohoo), to be told the only ones who could unblock port 25 worked business hours (oh joy), and to fill out the web form, which politely says it can take up to 2 days to be actioned), or to call my local Business Hub the next day (who I did call this morning, and they just transferred me back to level 1 broadband help desk, despite me asking if I could go stright to someone a bit more technical)

But finally this morning the front line support person that I spoke to actually understood the problem (having read the history), told me he could contact someone to deal with it, took my mobile so he could call me back ("in case I wanted to go out" - thoughtful is a good sign), called back 20 minutes later and said they were working on it, and about 40 minutes after that email started arriving. I got all my test messages I sent myself throughout yesterday while trying to debug the problem, so the good news is they were queued not dropped. Still haven't heard back from Telecom 2 hours later, but at least we got there in the end.

I hope this helps someone else ... because I could send email and not receive it it seemed unlikely at first that this was just a port 25 block implemented mostly the wrong way round (incoming but not outgoing), especially with postfix listening on both ports 587 and 25, so it was a bit of a goose chase, with not much help from Telecom until this morning.

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Uber Geek
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  Reply # 886423 29-Aug-2013 11:41
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Hello... Our robot found some keywords in your post, so here is an automated reply with some important things to note regarding broadband speeds.

 



 

If you are posting regarding DSL speeds please check that

 



 

- you have reset your modem and router

 


 

- your PC (or other PCs in your LAN) is not downloading large files when you are testing

 

- you are not being throttled by your ISP due to going over the monthly cap

 


 

- your tests are always done on an ethernet connection to the router - do not use wireless for testing

 


 

- you read this topic and follow the instructions there.

 



 

Make sure you provide information for other users to help you. If you have not already done it, please EDIT your post and add this now:

 



 

- Your ISP and plan

 


 

- Type of connection (ADSL, ADSL2, VDSL)

 


 

- Your modem DSL stats (do not worry about posting Speedtest, we need sync rate, attenuation and noise margin)

 


 

- Your general location (or street)

 


 

- If you are rural or urban

 


 

- If you know your connection is to an exchange, cabinet or conklin

 


 

- If your connection is to a ULL or wholesale service

 


 

- If you have done an isolation test as per the link above

 



 

Most of the problems with speed are likely to be related to internal wiring issues. Read this discussion to find out more about this. Your ISP is not intentionally slowing you down today (unless you are on a managed plan). Also if this is the school holidays it's likely you will notice slower than usual speed due to more users online.

 



 

A master splitter is required for VDSL2 and in most cases will improve speeds on DSL connections. Regular disconnections can be a monitored alarm or a set top box trying to connect. If there's an alarm connected to your line even if you don't have an alarm contract it may still try to connect so it's worth checking.

 



 

I recommend you read these two blog posts:

 



 

- Is your premises phone wiring impacting your broadband performance? (very technical)

 


 

- Are you receiving a substandard ULL ADSL2+ connection from your ISP?




I am the Geekzone Robot and I am here to help. I am from the Internet. I do not interact. Do not expect other replies from me.



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Ultimate Geek
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  Reply # 886441 29-Aug-2013 12:15
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Sorry to hear about the mission you had to get this fixed djaggar.

Port 25 filtering is applied by default to all Telecom Broadband connections. We block Port 25 in both directions.
The exception is smtp.xtra.co.nz.
send.xtra.co.nz does not use port 25.

The incoming mail server (pop3.xtra.co.nz) does not use port 25 and is not blocked, so hence you can receive mail without issue regardless of the port 25 setting.

Unfortunately with running two networks at the moment for Broadband (almost down to 1!), each has their own way of unblocking port 25. If the CSR does the wrong one, unfortunately it won't help. Apologies it took so long to get sorted!




My views are my own, and may not necessarily represent those of my employer.

 
 
 
 


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  Reply # 886442 29-Aug-2013 12:17
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Broadband helpdesk should be able to run the order to unblock port 25. Or send me an email "pl at telecom.co.nz" with your account number, phone line number that has broadband and your IP address (just in case it gets lost) and I can forward it onto the correct team.



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Master Geek
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  Reply # 886468 29-Aug-2013 12:45
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cbrpilot: Sorry to hear about the mission you had to get this fixed djaggar.

Port 25 filtering is applied by default to all Telecom Broadband connections. We block Port 25 in both directions.
The exception is smtp.xtra.co.nz.
send.xtra.co.nz does not use port 25.

The incoming mail server (pop3.xtra.co.nz) does not use port 25 and is not blocked, so hence you can receive mail without issue regardless of the port 25 setting.

Unfortunately with running two networks at the moment for Broadband (almost down to 1!), each has their own way of unblocking port 25. If the CSR does the wrong one, unfortunately it won't help. Apologies it took so long to get sorted!


Thank you for the quick helpful follow up, but can I please have a little clarification. 

When you say the exception is smtp.xtra.co.nz do you mean that is the one and only address the Port 25 unblocking is applied to ... as send.xtra.co.nz only uses 587? So if I want to do my own email, I have to support smtp on port 25, so I have to use smtp.xtra.co.nz. Is that correct? 

The bit about pop3, I'm not pop3-ing (or imap-ing) to your server, I pop3 (actually imap) to mine. My postfix relayhost is just set to smtp.xtra.co.nz and not smtp.xtra.co.nz:25 or smtp.xtra.co.nz:587 so I think it was defaulting to port 25 and that worked (so outboard wasn't blocked). However when you got an email for me, your block stopped you sending me an smtp request on port 25. I think that was the weird bit, because if you want to stop spam, it's really the connection from me you want to block, not the other way around. I get you do both ways just to be sure, but if somewhere new VDSL connections are set to block port 25 by default you were, for me at least, blocking the wrong half. 

Thanks again!



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Master Geek
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  Reply # 886471 29-Aug-2013 12:49
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plambrechtsen: Broadband helpdesk should be able to run the order to unblock port 25. Or send me an email "pl at telecom.co.nz" with your account number, phone line number that has broadband and your IP address (just in case it gets lost) and I can forward it onto the correct team.


It's working now thanks, but PM sent so if you want to follow it up so it doesn't happen to someone else (the help desk certainly could not remove the Port 25 block, nor could the level 2 support do it last night). My best guess is that because only the inbound (to me) route was blocked that something deeper was weird. Thanks again.

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Ultimate Geek
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  Reply # 886485 29-Aug-2013 13:04
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djaggar: 

Thank you for the quick helpful follow up, but can I please have a little clarification. 

When you say the exception is smtp.xtra.co.nz do you mean that is the one and only address the Port 25 unblocking is applied to ... as send.xtra.co.nz only uses 587? So if I want to do my own email, I have to support smtp on port 25, so I have to use smtp.xtra.co.nz. Is that correct? 


Hope this makes it more clear.  We have two policies:
Port 25 Filtering on (Default): Blocks all port 25 with the exception of smtp.xtra.co.nz
Port 25 Filtering off: completely unblocks all port 25

So if you have it unblocked, then sure, you can run whatever you want on port 25 and do not have to use smtp.xtra.co.nz.  








My views are my own, and may not necessarily represent those of my employer.



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Master Geek
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  Reply # 886494 29-Aug-2013 13:21
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cbrpilot:
djaggar: 

Thank you for the quick helpful follow up, but can I please have a little clarification. 

When you say the exception is smtp.xtra.co.nz do you mean that is the one and only address the Port 25 unblocking is applied to ... as send.xtra.co.nz only uses 587? So if I want to do my own email, I have to support smtp on port 25, so I have to use smtp.xtra.co.nz. Is that correct? 


Hope this makes it more clear.  We have two policies:
Port 25 Filtering on (Default): Blocks all port 25 with the exception of smtp.xtra.co.nz
Port 25 Filtering off: completely unblocks all port 25

So if you have it unblocked, then sure, you can run whatever you want on port 25 and do not have to use smtp.xtra.co.nz.  


Ok thanks, that's certainly clear, but makes my case all the more weird (a block on smtp.xtra.co.nz my incoming, your outgoing, port 25) which should never have had a port block in the first place. I'm definitely not using any other smtp relay (e.g. send.xtra.co.nz). When your CSR looks at my profile, they may well see port 25 filtering off, as that applies to everything except smtp.co.nz, which should never be blocked anyway ...

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Ultimate Geek
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  Reply # 886502 29-Aug-2013 13:32
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Can you send me your line number, and I"ll check which network you're on.
Our earlier network only blocks port 25 in one direction I believe.




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  Reply # 886504 29-Aug-2013 13:35
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djaggar:

Ok thanks, that's certainly clear, but makes my case all the more weird (a block on smtp.xtra.co.nz my incoming, your outgoing, port 25) which should never have had a port block in the first place. I'm definitely not using any other smtp relay (e.g. send.xtra.co.nz). When your CSR looks at my profile, they may well see port 25 filtering off, as that applies to everything except smtp.co.nz, which should never be blocked anyway ...


As I understand it, the default profile cbrpilot outline would include blocking your inbound port 25 - perhaps he can clarify. In which case, there's nothing unusual about it.




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Master Geek
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  Reply # 886510 29-Aug-2013 13:46
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Inphinity: 
As I understand it, the default profile cbrpilot outline would include blocking your inbound port 25 - perhaps he can clarify. In which case, there's nothing unusual about it.


Except that blocking my inbound connection is no use if you're trying to stop me spamming the world via port 25 (on my outgoing connection)... which I think is the intention of the port 25 blocks ...

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  Reply # 886512 29-Aug-2013 13:51
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djaggar:
Inphinity: 
As I understand it, the default profile cbrpilot outline would include blocking your inbound port 25 - perhaps he can clarify. In which case, there's nothing unusual about it.


Except that blocking my inbound connection is no use if you're trying to stop me spamming the world via port 25 (on my outgoing connection)... which I think is the intention of the port 25 blocks ...


The profile blocks port 25 inbound and outbound on your connection. The only SMTP server you can connect to inside the Telecom network is the Xtra SMTP server (to prevent your computer if it is virus infected from spamming the world) and the Xtra SMTP server does outbound filtering and allows us to have a view if your machine is infected or not and to disconnect you from the interwebs if you are :)

When the profile is set to unblocked, then all inbound and outbound port 25 isn't blocked.

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  Reply # 886513 29-Aug-2013 13:52
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djaggar: 
Except that blocking my inbound connection is no use if you're trying to stop me spamming the world via port 25 (on my outgoing connection)... which I think is the intention of the port 25 blocks ...


Yes, but

Port 25 filtering is applied by default to all Telecom Broadband connections. We block Port 25 in both directions.
The exception is smtp.xtra.co.nz.


My interpretation is that port 25 is blocked in both directions, between any host, EXCEPT inbound to smtp.xtra.co.nz. So your inbound is blocked, and your outbound to anything but smtp.xtra.co.nz is blocked. This can help reduce impact of customers who are failcakes at setting up their mail servers being exploited as an open relay.




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