vpn连接成功后ping其它IP出现TTL expired in transit错误

今天测试一双路由平台(双线路平台)、(香港出口和联通出口);发现通过联通平台vpn接入能ping通外网的IP,但是通过香港平台vpn接入ping外网的IP出现TTL expired in transit.错误,于是traceroute测试发现是路由环路导致TTL超时了。以下是测试时的出错信息:

C:>ping www.service-labs.com
Pinging www.service-labs.com [216.34.181.92] with 32 bytes of data:

Reply from 172.30.0.4: TTL expired in transit.
Reply from 172.30.0.4: TTL expired in transit.
Reply from 172.30.0.4: TTL expired in transit.
Reply from 172.30.0.4: TTL expired in transit.

Ping statistics for 216.34.181.92:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

C:>tracert -d www.service-labs.com

Tracing route to www.service-labs.com [216.34.181.92]  over a maximum of 30 hops

  1    45 ms    43 ms    44 ms  192.168.0.1
  2   145 ms    46 ms    51 ms  112.93.248.12
  3     *        *        *     Request timed out.
  4    48 ms    43 ms    45 ms  172.30.0.4
  5     *        *        *     Request timed out.
  6    48 ms    45 ms    47 ms  172.30.0.4
  7     *        *        *     Request timed out.
  8    50 ms    49 ms    45 ms  172.30.0.4
  9     *        *        *     Request timed out.
 10    56 ms    49 ms    47 ms  172.30.0.4
 11     *        *        *     Request timed out.
 12   119 ms    54 ms    51 ms  172.30.0.4
 13     *        *        *     Request timed out.
 14   251 ms    51 ms    49 ms  172.30.0.4
 15     *        *        *     Request timed out.
 16    55 ms    55 ms    51 ms  172.30.0.4
 17  ^C
C:>

通常导致TTL expired in transit.的原因有两个:

1)TTL值太小,TTL值小于你和对方主机之间经过的路由器数目;

2)路由器数量太多,经过路由器的数量大于TTL值。

问题分析:
根据traceroute得出的路由路径信息,发现路由卡死在172.30.0.4这个路由上,在到这个路由时产生了环路,互相踢皮球,确定是双路由平台(双线路平台)提供商的问题,提供商香港路由平台的架构我们是不清楚的,所以没办法向其建议解决,只能将发生的情况通知他们让他们做进一骤的检测!

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