[PLUG] iptables and protocol 50 and 51

[max.reid at saikonetworks.com]

Just to clarify, these are IP protcols, not TCP and UDP "port" numbers.  

Protocol 50 is Encapsulated Security Payload, which provides for both encryption
and authentication, AH just provides authentication.  Most folks only use ESP.

This is similar to OSPF being IP protocol 89, EIGRP 88 etc.

Regards,
Max


Quoting Terry Griffin <griffint at pobox.com>:

> On Mon, Mar 14, 2005 at 02:51:01PM -0800, Roderick A. Anderson wrote:
> > I have with a pretty much stock install of Fedora Core 3 with these lines 
> > in the /etc/iptables file.
> > 
> > 	-A RH-Firewall-1-INPUT -p 50 -j ACCEPT
> > 	-A RH-Firewall-1-INPUT -p 51 -j ACCEPT
> > 
> > What the heck is a protocol 50 or 51?  I am right about this being 
> > protocol.  --dport is the port ... right?
> > 
> > 
> 
> Those protocols are used by IPSec. File /etc/protocols describes
> them as:
> 
> esp     50      ESP             # encapsulating security payload
> ah      51      AH              # authentication header
> 
> Terry
> -- 
> Terry Griffin <griffint at pobox.com>
> http://www.blindchicken.com/~terryg/
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