2010/10/1 Mitja Mihelič <mitja.mihelic at arnes.si>: > > On 09/30/2010 05:02 PM, John Doe wrote: >> From: Mitja Mihelič<mitja.mihelic at arnes.si> >>> I am trying to use hping to chek the latency of our network. >>> Somehow things are not going to plan and I thought someone might be able >>> to shed some light on the subject. >>> Here is the setup: >>> (the IP addresses gvien here are fake, but they do represent the correct >>> state of the networking setup) >>> vlan interface IP mask >>> V2 eth0 192.168.20.20 32 >>> V4 eth1 172.16.4.40 32 >>> V6 eth2 172.16.6.60 32 >>> >>> The default route is set to eth1. >>> The idea is to use eth2 for pinging only, the other two interfaces are >>> used by another service and management access. >> Could you show the ifconfig and route outputs...? >> >> JD > The Centos version is 5.5. > > This is the kernel we are using > (http://rpms.mcnc.org/web100/el5/distro-compat/i386/): > 2.6.18-164.15.1.el5.web100PAE #1 SMP Mon May 17 17:01:51 EDT 2010 i686 > athlon i386 GNU/Linux > > The IP addresses are presented as private addresses, netmasks are real. > > Here is the ifconfig output: > [root at server ~]# ifconfig > eth0 Link encap:Ethernet HWaddr 00:16:35:82:45:A0 > inet addr:192.168.254.236 Bcast:192.168.254.239 > Mask:255.255.255.240 > inet6 addr: fe80::216:35ff:fe82:45a0/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:139602 errors:0 dropped:0 overruns:0 frame:0 > TX packets:58914 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:211203420 (201.4 MiB) TX bytes:4285647 (4.0 MiB) > Interrupt:186 Memory:dc000000-dc012800 > > eth1 Link encap:Ethernet HWaddr 00:16:35:82:45:A2 > inet addr:192.168.254.244 Bcast:192.168.254.247 > Mask:255.255.255.248 > inet6 addr: fe80::216:35ff:fe82:45a2/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:15 errors:0 dropped:0 overruns:0 frame:0 > TX packets:14 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:1130 (1.1 KiB) TX bytes:1116 (1.0 KiB) > Interrupt:194 Memory:da000000-da012800 > > eth2 Link encap:Ethernet HWaddr 00:15:17:C5:84:4D > inet addr:192.168.254.18 Bcast:192.168.254.23 > Mask:255.255.255.248 > inet6 addr: fe80::215:17ff:fec5:844d/64 Scope:Link > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 > RX packets:29 errors:0 dropped:0 overruns:0 frame:0 > TX packets:18 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:1000 > RX bytes:2280 (2.2 KiB) TX bytes:1236 (1.2 KiB) > Memory:dfde0000-dfe00000 > > lo Link encap:Local Loopback > inet addr:127.0.0.1 Mask:255.0.0.0 > inet6 addr: ::1/128 Scope:Host > UP LOOPBACK RUNNING MTU:16436 Metric:1 > RX packets:21 errors:0 dropped:0 overruns:0 frame:0 > TX packets:21 errors:0 dropped:0 overruns:0 carrier:0 > collisions:0 txqueuelen:0 > RX bytes:4240 (4.1 KiB) TX bytes:4240 (4.1 KiB) > > > And the route command output: > [root at server ~]# route -n > Kernel IP routing table > Destination Gateway Genmask Flags Metric Ref > Use Iface > 192.168.18.122 192.168.254.225 255.255.255.255 UGH 0 0 > 0 eth0 > 192.168.254.16 0.0.0.0 255.255.255.248 U 0 0 > 0 eth2 > 192.168.254.240 0.0.0.0 255.255.255.248 U 0 0 > 0 eth1 > 192.168.18.160 192.168.254.225 255.255.255.240 UG 0 0 > 0 eth0 > 192.168.254.224 0.0.0.0 255.255.255.240 U 0 0 > 0 eth0 > 192.168.1.64 192.168.254.225 255.255.255.192 UG 0 0 > 0 eth0 > 192.168.1.128 192.168.254.225 255.255.255.128 UG 0 0 > 0 eth0 > 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 > 0 eth2 > 0.0.0.0 192.168.254.241 0.0.0.0 UG 0 0 > 0 eth1 > > -- > Mitja > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > This may be too late, but came across this searching for my old iproute conversations. Each NIC needs its own "source based route" otherwise, it will use the sytem wide default route. In other words, add "nic specific default routes" in addition to the "system wide default route". Once you have nic specific source routes, you may notice a big difference between the following two seemingly identical commands: ping -I eth2 208.67.222.222 ping -I 192.168.x.y 208.67.222.222