Sendmail & port 25 help !!!

Sendmail & port 25 help !!!

Post by Ming Zha » Thu, 21 Nov 1996 04:00:00



Hi, there,

It is best to use your local machine to send fake mails. If you use the
mail server, you would leave something recognized.

-Ming


> Hi There,

> When I used the command "telnet xxx.washington.edu 25", it take me to
> the mail system of xxx machine. From here I can use any login name
> to send mail around the world.

> Is this a hole ? or any way for me to lock this ?
> I really don't want to disable port 25, because of send and receive the
> external mail.

> Thanks in advance

> ------------------------------------------------------------------------
> Minh Cao H.
> University of Washington
> Polar Science Center

> -------------------------------------------------------------------------

 
 
 

Sendmail & port 25 help !!!

Post by Minh Cao H » Fri, 22 Nov 1996 04:00:00


Hi There,

When I used the command "telnet xxx.washington.edu 25", it take me to
the mail system of xxx machine. From here I can use any login name
to send mail around the world.

Is this a hole ? or any way for me to lock this ?
I really don't want to disable port 25, because of send and receive the
external mail.

Thanks in advance

------------------------------------------------------------------------
Minh Cao H.
University of Washington
Polar Science Center

-------------------------------------------------------------------------

 
 
 

Sendmail & port 25 help !!!

Post by Mr. Yell » Tue, 26 Nov 1996 04:00:00



: When I used the command "telnet xxx.washington.edu 25", it take me to
: the mail system of xxx machine. From here I can use any login name
: to send mail around the world.

: Is this a hole ? or any way for me to lock this ?
: I really don't want to disable port 25, because of send and receive the
: external mail.

: Thanks in advance

Yep. you can send mail and basically pretend that you are anyone that
you want to be, using some fake headers etc. It's a problem with the
way that mail is sent using SNMP, not yours. The only way to make mail
more secure is to use digital signatures etc. at least as far as I am
aware anyway.

Cheers,

Tom.
--
     __  __
    /  \/  \      Thomas O'Dowd
    \ EIRE /      Systems Programmer.
  ___\    /___    Mitsubishi Chemical Corporation    
 / The Land of\   Yokohama Research Centre
 >  Love and  <  
 \___/\  /\___/   Contact:

     /_/\_\       Tel#  - (045) 963-3841      
     Flowers      Fax#  - (045) 963-3982

 
 
 

1. HELP: Can't telnet to port 23...but port 25 will work.

I am having problems telneting or ftping to my box. I can telnet to
port 25 (using both the IP or host name); however, I cannot telnet (to
port 23) or ftp using either the IP or the host name.

Hosts.deny/.allow are empty...

...inetd is obviously running...

...DNS is running, and other systems are successfully using it as a DNS
server...

...telnet and ftp lines in /etc/services are uncommented...

...a grep of running services in inetd.conf shows both ftp and telnet.

When telneting to the IP, I get:
   Connected to hostname.com
   Escape characher is...

   Connection closed

Lastly, there is a user other than root.

Could this be a DNS problem (I just set it up as a DNS server -- it was
my first time) -- remember, I could telnet to port 25 using the domain.

Sent via Deja.com http://www.deja.com/
Before you buy.

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