OpenVPN Support Forum

Posted: **Sat Apr 23, 2011 10:44 pm**

Can someone explain to me where did this values came from?

/*
 * Overhead added to packets by various protocols.
 */
#define IPv4_UDP_HEADER_SIZE              28
#define IPv4_TCP_HEADER_SIZE              40
#define IPv6_UDP_HEADER_SIZE              40

I cant find any reference to 28 and 40 in the packet structure of tcp and udp.

Posted: **Sun Apr 24, 2011 9:27 pm**

28 and 40 bytes for UDP and TCP traffic are "normal" in my view.
read up on the ethernet and tcp/udp protocols, e.g.
http://sd.wareonearth.com/~phil/net/overhead/

Posted: **Sun Apr 24, 2011 10:39 pm**

Thanks for the link

OpenVPN Support Forum

HEADER_SIZE in source

HEADER_SIZE in source

Re: HEADER_SIZE in source

Re: HEADER_SIZE in source