Server/mail/naming setup theory

[Dan Jenkins]

bscott at ntisys.com wrote:

 > On 13 Apr 2004, at 10:51pm, derek at derek.homeunix.org wrote:
 >> From work if I try to hit my web page by going to
 >> http://derek.homeunix.org, it times out ...
 >
 > That would be because Adelphia is blocking TCP port 80, which is the
 > well-known port for HTTP. It is not a DNS issue.

Not to start a flamewar, but I do want to point out Adelphia does 
prohibit running servers. I strongly
disagree with their policy, but I have known folk who have been harmed 
by it. Just FYI.

Yes, in my experience, Adelphia blocks port 80. They also actively scan 
for port 80 and port 25 being open.
I have had clients who had their Adelphia service terminated for 30 days 
because of those ports being open.
Presumably, their service would be terminated permanently if they were 
still doing it after 30 days.

Slightly off-topic story:
One of them was a 3-letter government agency which had a written contact 
allowing them to run a mail server from
the original cable company which Adelphia had subsequently bought. (I 
had made sure they got such a contract
when they signed up.) Adelphia basically said we don't honor any old 
contracts (not entirely unreasonable).
However, an attorney for this agency contacted Adelphia. About four 
hours after his phone call, the service was
reinstated and that client wasn't bothered again. <Moral of this story 
is left as exercise for the reader.>

Barring that situation, Adelphia's Terms of Service do prohibit running 
servers on their network. Specifically,
from their Service Agreement
(http://www.adelphia.com/esafety/Adelphia_Broadband_Internet_Access_Service_Agreement_2004-02-11.pdf):
(j) Local networking. Adelphia will support the connection of the
Adelphia Broadband Service to a single computer through a
recommended cable modem. Adelphia does not support the setup,
configurations and equipment maintenance of devices, including 
multi-function
devises that may contain a switch, router, firewall, etc., that
allow for the connection of multiple computers at the Site. ** You may not
operate a server of any type using the Adelphia Broadband Service. **
Later in the same agreement, they say:
(a) You agree not to use the Adelphia Broadband Service or any
Equipment or Software provided by Adelphia:
(v) to run a server of any type in connection with the Adelphia
Broadband Service, or to provide network or host services to others via
the Adelphia Broadband Service. Prohibited uses include, without
limitation, running servers for PPP, FTP, HTTP, DNS, POP, SMTP,
NNTP, PROXY, DHCP, IRC, TELNET, TFTP, SNMP and multi-user
interactive forums, and remapping of ports for the purpose of operating a
server on the network.

 >> the new domain that I recently registered www.deucedaily.org, hits
 >> zoneedit, and is forwarded to ww2.deucedaily.org:8080 ...
 >
 > That would be because Adelphia is *not* blocking TCP port 8080. When
 > you request <http://www.deucedaily.org/>, your browser makes a
 > connection to ZoneEdit's servers on TCP port 80. ZoneEdit's servers,
 > as you note, issue an HTTP redirect to
 > <http://ww2.deucedaily.org:8080>. The new URL specifies the
 > non-standard port number.

I have had Adelphia send a complaint letter to a client who also had 
port 8080 open. They moved their
web server to port 1234 and Adelphia never bothered them again.

 >> Mailing to aol accounts bounces back with error: server refused
 >> mail service.
 >
 > Yes. As I mentioned, AOL likes to block mail from IP address ranges
 > known to by dynamic, which would include your cable IP address.
 >
 > As someone else suggested, you can usually work around this by
 > configuring your own MTA to relay all outgoing mail through your
 > ISP's SMTP servers. That would be Adelphia, in your case. With
 > Sendmail, this is called using a "smart host". I am not familiar
 > with Postfix, so I cannot advise on how to configure it to do the
 > same. I'm sure someone else on this list can, though. You might
 > also check the Postfix documentation.

To send all your outbound email via Adelphia, for Postfix, edit
/etc/postfix/main.cf and add the line:
relayhost = smtp.bur.adelphia.net

Alternatively, using Postfix (and Sendmail, et al, for that matter), you 
can send just
AOL destined email to Adelphia SMTP server and still deliver all your 
other email yourself.

In /etc/postfix/main.cf,  add a line:
transport_maps = hash:/etc/postfix/transport

In /etc/postfix/transport, add these lines:
aol.com smtp:[smtp.bur.adelphia.net]
netscape.net smtp:[smtp.bur.adelphia.net]
earthlink.net smtp:[smtp.bur.adelphia.net]
rcn.net smtp:[smtp.bur.adelphia.net]

Note: These are the ones I've encountered so far which block dynamic 
address ranges.
Note: smtp.bur.adelphia.net is the New Hampshire/Vermont Adelphia SMTP 
server.
Your local Adelphia SMTP server may be different.

Then make the hash for it:
postmap /etc/postfix/transport

Let Postfix know about the change:
postfix reload

-- 
Dan Jenkins (dan at rastech.com)
Rastech Inc., Bedford, NH, USA --- 1-603-624-7272
*** Technical Support for over a Quarter Century