On 2/26/07, Jacques Beigbeder <[EMAIL PROTECTED]> wrote:
Hello,My question is related to PF performances with large state tables. FreeBSD : 5.5 hw.model: Intel(R) Xeon(TM) CPU 3.20GHz hw.physmem: 2138378240 = 2 Gb If I put a mail server 20 SMTP hits per second (thanks to spam...) 15 seconds per SMTP dialog 90 seconds for PF timeout tcp.close the state table will have: 20 * (90 + 15) * 2 ways = 5.000 entries Since any mail generates a few DNS queries (reverse DNS, + DSNRBL queries), the state table will also gets 2 ways * 60 seconds (timeout udp.multiple) * 5 (DNS queries) * 20 (connections) = 12.000 entries So I'll get around 20.000 entries, each of them have a short lifetime. Question: . is such a number a performance problem? It seems strange to constantly add and delete entries for DNS requests in the state table? . or do I have to write rules to avoid all the (unnecessary??) entries? As far as I understand, beginning with pass in quick proto udp from a.b.c.d port 53 to any ... same for TCP/25 ... is the trick.
[snip] Yes, keeping state on DNS traffic is quite expensive ;) This is mentioned in the series of 3 artilcles by the architect of pf, Daniel Hartmeier, at undeadly.org http://undeadly.org/cgi?action=article&sid=20060927091645&mode=expanded http://undeadly.org/cgi?action=article&sid=20060928081238&mode=expanded http://undeadly.org/cgi?action=article&sid=20060929080943&mode=expanded Try if just passing quick port 53 traffic without keeping state has a measurable postive impact. Or you could install a small not resource hungry caching nameserver like Bernstein's dnscache, which will save a lot of DNS and RBL ttraffic. Most of the time however, perl based virus scanning is the cause of less than expected performance of a mail server. =Adriaan= _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
