Since a few weeks, my mail server is under constant attack/probing. Postfix can handle it (they don't get past postscreen, they might not even try to go beyond postscreen), but the effect has become denial-of-service like. Local clients are having trouble connecting to the mail server to get mail out, for instance. The attack comes from some sort of botnet, the IP addresses change, though slowly: 95.183.220.2, 153.99.19.5, 84.19.727.93, 116.209.108.224, 85.145.10.210 are the addresses of the last 5 hours.
I've turned the mail server off for 10 minutes and on again, and currently the attack has stopped.
Can my EdgeRouter help against these kind of attacks?