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Message 11 of 17
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Re: Port Forwarding SMTP 25 on a Super Hub 3

It was likely put there for the same reason as 53, to deter people who might not know better from giving it a go and running publically accessible mail servers or DNS servers

Misconfigured mail servers running the risk of spam, and misconfigured DNS servers running the risk of being used in amplification attacks.
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Message 12 of 17
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Re: Port Forwarding SMTP 25 on a Super Hub 3

Yeah. 

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Message 13 of 17
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Re: Port Forwarding SMTP 25 on a Super Hub 3

Hi There,

I too stumbled upon this with a home lab setting up Exchange, turns out if you don't have a spare router to hand and want a quick fix (and are comfortable with JavaScript) the entire "Blocked Ports" check is just client-sided JavaScript validations, easily overridden with the dev tools in browsers.

That being said, a proper router with the Hub in modem mode would give you much more control.

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Message 14 of 17
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Re: Port Forwarding SMTP 25 on a Super Hub 3

Hi,

That is useful to know.

I ended up getting a new router and putting my VM Hub in Modem Mode.
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Message 15 of 17
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Re: Port Forwarding SMTP 25 on a Super Hub 3

There are 2 other options:

- If you are the SMTP server admin just configure it on a different non-default port that you don't use for anything else and that can be forwarded (e.g. 650 - just a random example)

- If you have a NAT behind the Virgin router (e.g. another router) then configure forwarding of a non-25 port (e.g. 650) on the Virgin router and then translation from it to port 25 on the other one.

In both cases configure your email client(s) to use SMTP on the non-default port, in this example 650.

 

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Alessandro Volta
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Message 16 of 17
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Re: Port Forwarding SMTP 25 on a Super Hub 3

The problem @Kanero is that other Email servers want to connect to port 25 they will not know of other ports to try.

In any case you need to use the hub in modem mode with a 1Gb router to forward port 25.

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BQM, Test for outgoing ports and L2TP VPN test
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Message 17 of 17
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Re: Port Forwarding SMTP 25 on a Super Hub 3

@legacy1 Yes thank you I just realised that I can connect with a client redirected to use the new port, but there is no incoming email because port 25 is the default port used by all other servers. So this is not a solution.

It's annoying as I had a hub 1 before and it did allow to forward port 25; hub 3 essentially broke my setup. I seem to have no choice to use the modem mode and another router although I did feel a bit "safer" being behind a second firewall.

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