We have an internet-facing router and it is significantly slowed down. We investigated the network traffic and came up with following information:

1. All the packet size is same (i.e. 40 bytes)

2. All different source IPs

3. Source port is the same for each request (i.e. 1234)

4. Same destination port (i.e. 80)

Is this a DDos attack? or any other attack signature?