Helping people with computers... one answer at a time.
Hotels and other locations that provided internet connectivity, both free and as an add-on service, often take steps to avoid being exploited by spammers. This can affect your ability to send email.
I checked in to my hotel which provides free high speed internet. All was well and good, except that after a while, I could no longer send email. I could receive all I wanted, but all my attempts to send failed. And the weird thing is that the next morning, sending mail worked ... again, for a while. What's going on?
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I've run into this as well. It's very strange and even frustrating, but once I understood it, it began to make sense.
And understanding it also allowed me to work around it.
But it's the kind of thing that I wouldn't expect the front desk to be able to help with at all. You and I? We're kind of on our own.
The root cause of all this?
Spammers.
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Port 25
SMTP is an acronym for Simple Mail Transfer Protocol which is the protocol used to transport email messages from computer to computer until they reach their destination. SMTP is used ... continue reading.
From the Ask Leo! Glossary
You may already know, but when you send email your desktop email program connects to a remote email server, and communicates on a particular "port".
Port 25 happens to be the default SMTP mail sending port. It's used not only to send email from your computer to the email server that you use, but also between email servers as they deliver email all across the internet.
Hotels and Port 25
Many hotels (I'll use the term to refer not only to hotels but also any place that provides internet connectivity for free or for a fee) are intercepting mail being sent to any mail server on port 25. Instead of connecting to the server your email program requests, they intercept and connect to their email server instead.
Even though your mail program is configured to send your mail through the SMTP server of, say, your isp, the hotel's infrastructure sends it through their email server.
And now that they're controlling it they then often impose a cap on the amount of email you can send.
Reasons for Interception
Naturally the first reaction is to wonder why in heaven's name would a hotel, or any one for that matter, want to intercept and limit the amount of email I can send? Isn't that my business?
Well, yes and no.
Email you send while you're at the hotel could possibly be traced back to the hotel and even cause the hotels internet connection to be blacklisted.
Blacklisted?
Yes, blacklisted.
If you are a spammer, or your machine is infected with a spam-sending zombie, sending unrestricted email that originates from the hotel's IP address some anti-spam technologies will eventually blacklist the source - the IP address of the hotel.
If that happens you, the other hotel guests and perhaps even the hotel staff themselves may be able to send all the email you want, only to have it be filtered as spam and never reach its destination.
By limiting the number of emails you can send per day the hotel effectively restricts your ability to be a spammer, and dramatically reduces the possibility that their network could be accused of being a source of spam.
Work-arounds
There are workarounds.
And yes, the spammers can use some of these as well, should they be so motivated. However even by blocking the default case hotels can at least make a signficant dent in the problem.
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Use web mail. If your ISP has a web interface, than can be a quick way to be able dash off that important email with no further thought.
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Use an alternate port. If your email provider supports this, you may be able to configure your email client to connect via a port other than 25. If they provide an SMTP over SSL connection (more and more common these days) that's often via port 465 or 587. Being SSL they are significantly more difficult to intercept and thus typically left alone. Your ISP may also provide traditional SMTP access over an alternate port such as 26. The good news about either choice is that things should continue to work when you get back home without having to "undo" anything.
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Use a VPN. If you or your corporation have the ability to connect using a VPN, or Virtual Private Network, that connection bypasses these types of redirections.
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Use SSH tunneling. This gets pretty geeky, and requires an ISP willing to grant you SSH access, but also bypasses all port 25 intercepts.
I don't really blame the hotels, they're trying to address a very real and serious problem. I do wish that they had better information available about what they're doing, or at least a warning of some sort. But ultimately I blame the spammers and the purveyors of malware that have forced the hotels and others into the position of having to take these types of actions.
About that Internet Connection...
One final thought about that internet connection that's being provided to you.
It's essentually the moral equivalent to an open Wifi hotspot, even if you're not using Wifi.
The hotel is acting as your ISP, and as I've said before, your ISP can see everything you do. And yes, there is anecdotal evident that hotels might be looking at your unencrypted data.
On top of that, depending on how the network is configured even connections "nearby" your wired internet connection may also be able to see your data passing by, exactly like an open WiFi hotspot.
The solution?
Whenever you are using an internet connection provided by a third party that you know little or nothing about treat it like an open WiFi hotspot.
(This is an update to an article originally published December 19, 2005.)
Article C2496 - December 19, 2012 « »
Leo A. Notenboom has been playing with computers since he
was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed.
After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers
to common computer and technical questions. More about Leo.
August 25, 2011 11:53 PM
Ive left that hotel. Ive even left the island. im in Greece. and i still cant receive email, though i can send it. the last three entries in my in box are
Welcome!
To access the network, please open up your browser and connect to a web site.
Or, you may click here to access the login page.
i never even logged into this server, but sense then i cant get email.
please help.
ps. i can still get it on my phone and ipads but not my macbook
September 15, 2012 3:33 PM
Another solution is to get a $20 per year smtp account at www.travelsmtp.com. They run their servers on lots of ports, also on 443 (https) with SSL. No firewall, ISP or hotel will ever be able to block that, unless they block regular internet traffic (which is never the case of course).
December 21, 2012 1:33 PM
Leo, I find that most SMTP servers now support Port 587 WITH authentication without SSL in order to avoid Port 25 blocking of its subscribers when not directly connected. When SSL is offered on an SMTP server, I find it's almost always on Port 465.
Season's Greetings
December 21, 2012 3:22 PM
I had the same problem, but it was not at a hotel. It was anywhere I could get a wireless network connection. I went to stay at my nephews feeling quite happy I could connect whilst away from the office. I could receive ALL mail, but I could send none.
In my case it was purely because my ISP account had a static IP address.
The problem was only overcome when I went onto Openzone account with my ISP, to use wherever place available.
December 31, 2012 12:44 PM
There's another possible cause, though in this case sending never works at all. If you get "relaying denied" there is a strong possibility that your ISP's servers have simply rejected the connection from the hotel's servers. This can because "relaying" is disabled in your account settings, or by your ISP, or because the hotel server's security, anti-virus and anti-spam configuration doesn't meet your ISP's requirements, which is determined during a handshake process when the hotel's server attempts to establish a connection. In the latter case, alerting the hotel's - or its ISP's - IT staff may resolve the problem, at least for future guests.