Salut, am nevoie sa calculez dimensiunea medie a unui request DNS (cerere si raspuns). M-am gandit sa loghez cu tcmdump traficul pentru o perioada de timp data si apoi sa fac media size-urillor requesturilor:
# tcpdump -nn -i eth0 | egrep -i "\.53(\ >|: ) 09:45:46.054966 a.b.c.d.53 > x.y.z.t.53: 35065 1/11/12 (513) (DF) 09:45:46.099954 a.b.c.d.53 > x.y.z.t.53: 39837 NXDomain 0/1/1 (110) (DF) 09:45:46.225132 x.y.z.t.53 > 206.191.0.210.53: 5392+ [1au] PTR? 148.142.109.220.in-addr.arpa. (57) 09:45:46.745089 x.y.z.t.53 > 64.105.124.154.32770: 7511*- 1/2/3 A x.y.z.t (137) 09:45:47.945265 x.y.z.t.53 > 210.138.175.244.53: 1323 [1au] A? mcn-ns1.miyazaki-catv.ne.jp. (56) 09:45:47.945361 x.y.z.t.53 > 210.138.175.244.53: 26323 [1au] A? mcn-ns2.miyazaki-catv.ne.jp. (56) 09:45:47.945382 x.y.z.t.53 > a.b.c.d.53: 63479+ [1au] PTR? 52.68.105.219.in-addr.arpa. (55) 09:45:47.945420 x.y.z.t.53 > 210.138.175.244.53: 62514 [1au] A? mcn-ns3.miyazaki-catv.ne.jp. (56) 09:45:47.976022 210.138.175.244.53 > x.y.z.t.53: 26323-% 0/3/4 (162) 09:45:47.976025 210.138.175.244.53 > x.y.z.t.53: 1323-% 0/3/4 (162) 09:45:47.976522 210.138.175.244.53 > x.y.z.t.53: 62514-% 0/3/4 (162) 09:45:47.977423 x.y.z.t.53 > a.b.c.d.53: 64025+ [1au] A? mcn-ns2.miyazaki-catv.ne.jp. (56) 09:45:47.977455 x.y.z.t.53 > a.b.c.d.53: 62921+ [1au] A? mcn-ns1.miyazaki-catv.ne.jp. (56) 09:45:47.977764 x.y.z.t.53 > a.b.c.d.53: 22677+ [1au] A? mcn-ns3.miyazaki-catv.ne.jp. (56) 09:45:48.245117 x.y.z.t.53 > 210.138.175.244.53: 57033 [1au] PTR? 148.142.109.220.in-addr.arpa. (57) 09:45:48.275959 210.138.175.244.53 > x.y.z.t.53: 57033-% 0/3/4 (184) 09:45:48.276889 x.y.z.t.53 > a.b.c.d.53: 60245+ [1au] PTR? 148.142.109.220.in-addr.arpa. (57) 09:45:49.771152 x.y.z.t.53 > a.b.c.d.53: 7081+ [1au] PTR? 139.116.188.205.in-addr.arpa. (57) 09:45:49.804602 a.b.c.d.53 > x.y.z.t.53: 7081 1/2/3 (176) (DF) [...] unde x.y.z.t e serverul meu (pe care fac DNS caching) si a.b.c.d este serverul meu de DNS. Nu sunt sigur daca valoarea din campul 5 (35065, 39837, ...) reprezinta dimeansiunea in bytes a cererii sau nu. Daca nu, cum fac sa am afisat si dimensiunea totala in bytes a requestului, inclusiv dimensiunea header-ului pachetului de IP? Mersi. --- Detalii despre listele noastre de mail: http://www.lug.ro/
