Neocekavana zmena default gateway

[Radek Krejča]

Zapnul jsem logovani icmp redirectu:

Uplne mi neni jasne toto:

icmp redirect from 10.4.4.122: 10.4.29.242 => 10.4.4.121
icmp redirect from 10.4.4.122: 10.4.29.242 => 10.4.4.121
icmp redirect from 10.4.4.122: 10.4.29.242 => 10.4.4.121
icmp redirect from 127.0.0.1: 10.4.29.242 => 10.4.29.242
icmp redirect from 127.0.0.1: 10.4.29.242 => 10.4.29.242
icmp redirect from 127.0.0.1: 10.4.29.242 => 10.4.29.242
icmp redirect from 127.0.0.1: 10.4.29.242 => 10.4.29.242


Chapu, ze napred chodilo z 10.4.4.122, ale proc pak ze 127.0.0.1? Nebo chapu spatne ten zaznam?

Jinak jeste jsem koukal s kolegou do /usr/src/sys/netinet/ip_icmp.c a tam je pasaz:

                        printf("icmp redirect from %d.%d.%d.%d: "
                               "%d.%d.%d.%d => %d.%d.%d.%d\n",
                               (int)(src >> 24), (int)((src >> 16) & 0xff),
                               (int)((src >> 8) & 0xff), (int)(src & 0xff),
                               (int)(dst >> 24), (int)((dst >> 16) & 0xff),
                               (int)((dst >> 8) & 0xff), (int)(dst & 0xff),
                               (int)(gw >> 24), (int)((gw >> 16) & 0xff),
                               (int)((gw >> 8) & 0xff), (int)(gw & 0xff));
                }
                /*
                 * RFC1812 says we must ignore ICMP redirects if we
                 * are acting as router.
                 */
                if (V_drop_redirect || V_ipforwarding)
                        break;

Prijde mi, ze ten komentar neodpovida skutecnosti ve chvili, kdy tech icmp redirectu prijde fakt hodne moc. Pri tom logovani totiz chodi proad neco, ale ve chvili, kdy se mi zacne plnit log opravdu masivne, tak k te zmene ip dojde.

Radek