能ping通，却不能traceroute通？

ljok30

如题，详细见下面配置，只有一块网卡，虚拟出一个网卡，开启ip转发：

# ifconfig -a
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1
        inet 127.0.0.1 netmask ff000000
pcn0: flags=1100843<UP,BROADCAST,RUNNING,MULTICAST,ROUTER,IPv4> mtu 1500 index 2
        inet 192.168.16.107 netmask ffffff00 broadcast 192.168.16.255
        ether 0:c:29:4f:e1:a6
pcn0:1: flags=1100843<UP,BROADCAST,RUNNING,MULTICAST,ROUTER,IPv4> mtu 1500 index 2
        inet 10.10.168.176 netmask ff000000 broadcast 10.255.255.255
#     
# ifconfig -a
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1
        inet 127.0.0.1 netmask ff000000
bash-3.00# ifconfig -a
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1
        inet 127.0.0.1 netmask ff000000
pcn0: flags=1100843<UP,BROADCAST,RUNNING,MULTICAST,ROUTER,IPv4> mtu 1500 index 2
        inet 192.168.16.107 netmask ffffff00 broadcast 192.168.16.255
        ether 0:c:29:4f:e1:a6
pcn0:1: flags=1100843<UP,BROADCAST,RUNNING,MULTICAST,ROUTER,IPv4> mtu 1500 index 2
        inet 10.10.168.176 netmask ff000000 broadcast 10.255.255.255
bash-3.00# ping -i pcn0:1 -s 192.168.16.1
PING 192.168.16.1: 56 data bytes
64 bytes from 192.168.16.1: icmp_seq=0. time=239. ms
64 bytes from 192.168.16.1: icmp_seq=1. time=169. ms
64 bytes from 192.168.16.1: icmp_seq=2. time=11.9 ms
64 bytes from 192.168.16.1: icmp_seq=3. time=2.17 ms
64 bytes from 192.168.16.1: icmp_seq=4. time=314. ms
64 bytes from 192.168.16.1: icmp_seq=5. time=76.3 ms
^C
----192.168.16.1 PING Statistics----
6 packets transmitted, 6 packets received, 0% packet loss
round-trip (ms)  min/avg/max/stddev = 2.17/135./314./1.3e+02
bash-3.00# traceroute -i pcn0:1 192.168.16.1
traceroute to 192.168.16.1 (192.168.16.1), 30 hops max, 40 byte packets
1  * * *
2  * * *
3  * * *
4  * * *
5  * * *
6 ^C
bash-3.00# ndd -get /dev/ip ip_forwarding
1
bash-3.00#

yuhuohu

不奇怪，Ping和traceroute虽然都是icmp报，可报文类型不同，目标主机可能拒绝响应icmp的traceroute报文，仅响应icmp的echo和echo_reply

ljok30

按照你的说法，那下面的情况又怎么解释呢？下面的情况说明远程主机是响应traceroute的报文的，这就是奇怪的地方。

bash-3.00# traceroute -i pcn0 192.168.16.1
traceroute to 192.168.16.1 (192.168.16.1), 30 hops max, 40 byte packets
1  192.168.16.1 (192.168.16.1)  0.000 ms  9.843 ms *
bash-3.00#

race

一个机器分配俩IP时容易出现那样的问题，个人感觉traceroute源地址问题。加个-a看看

yuhuohu

traceroute -i pcn0:1 192.168.16.1 你得pcn0:1是10网段，基本上死也追不到192.168.16.1得，就只能用pcn0才行

ping -i pcn0:1 -s 192.168.16.1这个嘛，基本上不用管这个哪，

pcn0和192一个网段，本来就应该用ping -i pcn0 -s 192.168.16.1

LZ还是用规范做法吧。不要非得用不同网段得网卡去测试另一个接口得网络吧

[ 本帖最后由 yuhuohu 于 2007-9-20 10:39 编辑 ]

ljok30

其实我就是想试验ip转发的功能，看是否能在虚拟网络接口之间转发！

yuhuohu

yun,那不是这样子试验滴..

host1---------pcn0:1        solaris        pcn0--------------host2

host1 ping host2
or
host2 ping host1

ljok30

我明白，我这样做只是把问题简单化，要不然你怎么就敢肯定不是host1到solaris出问题了呢？现在的问题就是host1 ping不通host2，所以才会有这个想法，测试一下本机的两个网络接口能不能正常转发数据包，确定问题所在嘛！

ljok30

我这样都通是不是表明我的ip转发没有问题呢，但是一旦把192。168。16。107（这个是我本机的ip）换成别的同一网段的机器就traceroute不通呢？

bash-3.00# ping -i pcn0:1 -s 192.168.16.107
PING 192.168.16.107: 56 data bytes
64 bytes from ljok (192.168.16.107): icmp_seq=0. time=0.252 ms
64 bytes from ljok (192.168.16.107): icmp_seq=1. time=0.231 ms
64 bytes from ljok (192.168.16.107): icmp_seq=2. time=0.200 ms
64 bytes from ljok (192.168.16.107): icmp_seq=3. time=0.194 ms
64 bytes from ljok (192.168.16.107): icmp_seq=4. time=0.198 ms
^C
----192.168.16.107 PING Statistics----
5 packets transmitted, 5 packets received, 0% packet loss
round-trip (ms)  min/avg/max/stddev = 0.194/0.215/0.252/0.025
bash-3.00# traceroute -i pcn0:1 192.168.16.107
traceroute to 192.168.16.107 (192.168.16.107), 30 hops max, 40 byte packets
1  ljok (192.168.16.107)  0.000 ms  0.000 ms  0.000 ms
bash-3.00#

yuhuohu

原帖由 yuhuohu 于 2007-9-20 10:57 发表
yun,那不是这样子试验滴..

host1---------pcn0:1        solaris        pcn0--------------host2

host1 ping host2
or
host2 ping host1

关掉IP FORWARD，如果不通，再开ip forward，如果通，就说明ip forward起作用了嘛。。。

host1 ping host2
or
host2 ping host1
or
host1 ping pcn0
or
host2 ping pcn0:1
至于traceroute命令，在细节方面你可以多试验各种角度的tracert，经验多了就知道什么时候通与不通了