Re: iptables question

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]



Joseph L. Casale wrote:
When do you know you need the "-m multiport" option? I see examples with -dport xx:xxx for example that sometimes use it and sometimes don't?
I have read the man page and see what "-m multiport" requires, but don't see the requirement involving its use.

Thanks!
jlc

I'll take a guess but am happy to be corrected if someone knows better...

My understanding is that --dport can only specify a single port (--dport 80) or port range (--dport 137:139) inclusive. Use of the multiport module allows up to 15 ports (or port ranges) to be specified.

As for a potential usage - off the top of my head, suppose you wanted to open ports 137-139 and 445 for SMB/Samba. This could be achieved with a single rule using the multiport module whereas 2 individual rules would otherwise be needed. Again, suppose you wanted to open ports 21 (FTP), 22 (SSH) and 110 (POP3) to a select IP address - you could do this in a single rule rather than 3 individual rules which opens up possibilities for optimizing/minimizing the number of iptables rules within a chain.

Ned
_______________________________________________
CentOS mailing list
CentOS@xxxxxxxxxx
http://lists.centos.org/mailman/listinfo/centos

[Index of Archives]     [CentOS]     [CentOS Announce]     [CentOS Development]     [CentOS ARM Devel]     [CentOS Docs]     [CentOS Virtualization]     [Carrier Grade Linux]     [Linux Media]     [Asterisk]     [DCCP]     [Netdev]     [Xorg]     [Linux USB]
  Powered by Linux