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postfix and mail header
https://forum.linode.com/viewtopic.php?f=11&t=1845		 Page 1 of 1
Author:  jlinos [ Mon Aug 29, 2005 2:27 am ]
Post subject:  postfix and mail header
when i look in the file: /var/mail/username i see a heaer line like this:

Code:
Received: from 172.16.4.32 (unknown [81.181.177.254])


I use it to put some bad ips in my postfix config files to stop spam.

But i do not know which one to get from the above line and use it in my bad ips list. and what each one means. If anybody can enlighten me I would appreciatte it.

Thank you in advance

jgabios
Author:  NeonNero [ Mon Aug 29, 2005 3:01 am ]
Post subject: 
The second one (81.181.177.254) would be the actual IP address of the sender server (or client). This log line (which would also appear as an added "Received:" header in successfully transported mail) indicates that the sender tries to pass itself off with the IP address 172.16.4.32, which just belongs to a range that is used for a private network.

Code:
3. Private Address Space

   The Internet Assigned Numbers Authority (IANA) has reserved the
   following three blocks of the IP address space for private internets:

     10.0.0.0        -   10.255.255.255  (10/8 prefix)
     172.16.0.0      -   172.31.255.255  (172.16/12 prefix)
     192.168.0.0     -   192.168.255.255 (192.168/16 prefix)

Excerpt from RFC 1918, the whole document can be read here:
http://www.faqs.org/rfcs/rfc1918.html

The IP address range 81.181.176.0 - 81.181.177.255, however, belongs to "SC Estel Service Net Srl" in Romania. You might also get in touch with them if you believe they have an abusive client on their network.
http://www.ripe.net/whois?form_type=sim ... rch=Search
Author:  jlinos [ Mon Aug 29, 2005 7:31 am ]
Post subject:  thanks
thank you.
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