Re: Ever heard of a mail server which blocks by type of IP address?
From: David Robbins (drobbins@eprisolutions.com)
Date: 04/01/03
- Next message: Robert Burris: "Re: Sad news, Bill Gates dead at 47"
- Previous message: David Robbins: "Re: Here is an interesting SPAM trick"
- In reply to: George Hester: "Ever heard of a mail server which blocks by type of IP address?"
- Next in thread: PilotKR: "Re: Ever heard of a mail server which blocks by type of IP address?"
- Reply: PilotKR: "Re: Ever heard of a mail server which blocks by type of IP address?"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]
From: "David Robbins" <drobbins@eprisolutions.com> Date: Tue, 1 Apr 2003 07:33:48 -0500
yes, there is a listing somewhere that at least some isp's use on their mail
servers to block connections from specific ip's. the one i have run against
is not checking the headers, it checks the ip of the smtp server that is
trying to forward mail to it against a list of dialup ip blocks. if the
'server' connecting to it is in a dialup block it is summarily rejected, the
idea being that no legitimate mail server would be on a dialup line.
"George Hester" <hesterloli@hotmail.com> wrote in message
news:OWIJgx99CHA.1300@TK2MSFTNGP09.phx.gbl...
I have heard of and seen that some ISPs that provide POP3 mail are able to
block incoming mail to their servers which originates from a DHCP assigned
address. My queston is this:
If I picked a random IP address out of a hat could I determine whether it
was a DHCP assigned IP address or not? If not what tools would I need to
determine if it was or not?
Finally, is this similar to blocking based on whether the headers in fact
point back to a valid network?
In other words, if the headers were forged would then this disable the
ability of an ISP to accomplish the above? It seems that verifying this in
headers requires too much work on the part of mail servers. Thanks.
-- George Hester __________________________________
- Next message: Robert Burris: "Re: Sad news, Bill Gates dead at 47"
- Previous message: David Robbins: "Re: Here is an interesting SPAM trick"
- In reply to: George Hester: "Ever heard of a mail server which blocks by type of IP address?"
- Next in thread: PilotKR: "Re: Ever heard of a mail server which blocks by type of IP address?"
- Reply: PilotKR: "Re: Ever heard of a mail server which blocks by type of IP address?"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] [ attachment ]
Relevant Pages
|
