Lazarus Long
join:2000-11-24
Saint Louis, MO |  [HSI] Outbound Acces to Port 25 blocked except for charter.net
Starting today, I can no longer send out e-mail to any server other than smtp.charter.net using port 25.
Has anyone else seen this?
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Always listen to experts. They'll tell you what can't be done, and why. Then do it. |
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WiseOldNerd
De gustibus non est disputandum
Premium
join:2001-11-25
Phoenix, AZ | Re: [HSI] Outbound Acces to Port 25 blocked except for charter.n
Mine has been blocked from day one. I just use the alternative port provided by my mail service and gmail and forget about it. No big deal.
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My perception is REALITY |
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NormanS
Premium,MVM
join:2001-02-14
San Jose, CA
 ·Pacific Bell - SBC
| reply to Lazarus Long
In the Spring of 2005, SBC blocked outbound port 25 for all of their customer. Didn't affect me, for the most part; I just used:
smtp.aim.com:587
smtp.aol.com:587
smtp.gmail.com:587
smtp.gmx.net:587
smtp.myrealbox.com:465
smtpauth.sbcglobal.net:587
Gmail also uses port 465 ('smtp.gmail.com:465'). And Yahoo! recently added port 465, as well (used to use port 587). Any third party Email Service Provider which does not offer SMTP message submission on an alternate message submission port really didn't want your business, anyway. Why continue to use them?
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Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum |
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BlakePaulson
join:2008-08-06
Alexandria, MN | reply to Lazarus Long
I use 587 on my host's server... took me a week or two to figure it out when I first got charter's service.
Then once I figured it out it was an easy fix... never had an issue. |
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ArkiMage
join:2001-06-30
Kingsport, TN
| reply to Lazarus Long
What Charter is doing here is a _good_ thing and I wish all other ISPs would follow suit. If you are forced to send all your outbound email through your ISP's mail server then hopefully they'll notice if you're sending a few million and block you from doing so. If you can make arbitrary SMTP port 25 connections to anywhere you want then admins have to continue to contend with the millions of zombied PCs spewing SPAM without their owner's knowledge. We turn away 2 to 3 SMTP connections per second which originate not from mail _servers_ but rather from PCs on Cable and DSL IPs primarily. ISPs could help to greatly reduce the flow of SPAM if they'd all do this.
Oh, and my local Charter network is not blocking outbound :25 by the way.
Oh and guess what? A lot of folks don't realize this but you don't have to (generally) connect to the mail server associated with a domain name to send email for that domain. Put another way, I just sent an email that shows as coming from myusername@gmail.com to smtp.charter.net and received it at the destination address a few seconds later. I did *not* have to send the email *to* Gmail's servers. It went from me to smtp.charter.net then to the email server for the domain I was sending it to. When received it showed as coming from me@gmail.com, the mail *servers* it traveled through to get there are generally independent of the addressing, and in this case didn't ever even touch a gmail mail server. Yes I know there can be negatives associated with that as well. Just pointing out something that is commonly misunderstood about sending email... |
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NormanS
Premium,MVM
join:2001-02-14
San Jose, CA
·Pacific Bell - SBC
| said by ArkiMage  :What Charter is doing here is a _good_ thing and I wish all other ISPs would follow suit. AT&T and Comcast do it. AT&T Worldnet and AT&T FastAccess just block outbound port 25. Period. While 'at&t Yahoo! HSI' blocked by default, they do unblock on request. Comcast blocks reactively; if their Sandvine appliance detects an abnormally high volume of SMTP traffic, they will push a port 25 blocking modem config file on their customer. AOL, Cox, and Earthlink also block outbound port 25.
Oh, and my local Charter network is not blocking outbound :25 by the way.
Ah. Explains why I see Charter residential IP addresses in my MTA logs.
Oh and guess what? A lot of folks don't realize this but you don't have to (generally) connect to the mail server associated with a domain name to send email for that domain.
I have a number of such configurations. I have a free Fastmail account. IMAP access only, no SMTP server. It is in the 'fastmail.jp' domain. I also have a free Yahoo! Mail account in the 'yahoo.co.jp' domain. I have set it up so the 'fastmail.jp' email goes out through 'smtp.mail.yahoo.co.jp'. And I can send email "From:" my own domain through 'smtp.att.yahoo.com', as well.
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Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum |
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Lazarus Long
join:2000-11-24
Saint Louis, MO
| reply to ArkiMage
I agree it's a good thing, although inconvenient for some.
I just wish they would have notified me. One day Port 25 worked, next day it didn't.
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Always listen to experts. They'll tell you what can't be done, and why. Then do it. |
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