topic difference between GRE and IPIP tunnel in Network Security

difference between GRE and IPIP tunnel

mkirankumar — Fri, 21 Feb 2020 07:52:15 GMT

Hi!!!

I want to know when tunnel is configured, which mode is more affective in terms of encryption and less overhead.

Thanks in Advance

Kiran

Re: difference between GRE and IPIP tunnel

sstudsdahl — Mon, 17 Jan 2005 20:28:30 GMT

Kiran,

When talking encryption, neither a GRE or IPIP tunnel will encrypt the traffic on their own. This process needs to be done using a second mechanism such as IPSec.

In terms of less overhead, the GRE header is 24 bytes and an IP header is 20 bytes.

When a GRE tunnel is built, the original packet is encapsulated within a GRE (IP Protocol 47) packet and send to the configured tunnel destination. Similarly, when using IPIP tunnels, the original packet to be sent is encapsulated within a new IP packet and transmitted to the tunnel destination. When looking at an IPIP packet with a protocol analyzer, the packet will appear to have two IP headers within it.

Another thing to consider with the two tunnel types is that a GRE tunnel has the ability to acknowledge the receipt of packets similar to TCP communications. The IPIP tunnel method has no such mechanism as it inherits the stateless behavior of a raw IP packet, similar to UDP based communications.

Steve

Re: difference between GRE and IPIP tunnel

aaron mwenda — Mon, 03 Feb 2025 07:32:23 GMT

Am using GRE tunnel and suddenly it has stopped working i tried to delete it and reconfigure but still am experiencing the same problem ...any ideas guys coz currently am thinking of switching to ip tunnel