rp_filter 导致单边网络异常。（已解决）

lmtwl

环境：
        一台服务器 配置电信eth0、联通eth1双线策略。机房拓扑的原因。电信、联通网关的arp 是一样的。 系统的默认rp_filter 设置为1 ，在这种机房拓扑下数据流量是没有任何异常。但是由于环境需要开启rp_filter 的值为2 。在这种机房拓扑下出现流量异常情况如下：


           1、电信接口 eth0 流量只有出流量；eth1接口流量包括了联通的进出流量跟电信eth0 的进流量。


           请问这种情况如何解决。

Riet

rp_filter的值有2么？
我貌似只记得 arp_announce 和arp_ignore 有2

还有你这个情况我怎么觉得应该是设置成rp_filter = 0 arp_filter =0

Riet

rp_filter
BOOLEAN
1
do source validation by reversed path, as specified in RFC1812. Recommended option for single homed hosts and stub network routers. Could cause troubles for complicated (not loop free) networks running a slow unreliable protocol (sort of RIP), or using static routes.
0
No source validation.

arp_filter
BOOLEAN
1
Allows you to have multiple network interfaces on the same subnet, and have the ARPs for each interface be answered based on whether or not the kernel would route a packet from the ARP'd IP out that interface (therefore you must use source based routing for this to work). In other words it allows control of which cards (usually 1) will respond to an arp request.
0
(default) The kernel can respond to arp requests with addresses from other interfaces. This may seem wrong but it usually makes sense, because it increases the chance of successful communication. IP addresses are owned by the complete host on Linux, not by particular interfaces. Only for more complex setups like load-balancing, does this behaviour cause problems.
arp_filter for the interface will be enabled if at least one of conf/{all,interface}/arp_filter is set to TRUE,it will be disabled otherwise
arp_announce
INTEGER
Define different restriction levels for announcing the local source IP address from IP packets in ARP requests sent on interface:
0
(default) Use any local address, configured on any interface
1
Try to avoid local addresses that are not in the target's subnet for this interface. This mode is useful when target hosts reachable via this interface require the source IP address in ARP requests to be part of their logical network configured on the receiving interface. When we generate the request we will check all our subnets that include the target IP and will preserve the source address if it is from such subnet. If there is no such subnet we select source address according to the rules for level 2.
2
Always use the best local address for this target. In this mode we ignore the source address in the IP packet and try to select local address that we prefer for talks with the target host. Such local address is selected by looking for primary IP addresses on all our subnets on the outgoing interface that include the target IP address. If no suitable local address is found we select the first local address we have on the outgoing interface or on all other interfaces, with the hope we will receive reply for our request and even sometimes no matter the source IP address we announce.
The max value from conf/{all,interface}/arp_announce is used.
Increasing the restriction level gives more chance for receiving answer from the resolved target while decreasing the level announces more valid sender's information.
arp_ignore
INTEGER
Define different modes for sending replies in response to received ARP requests that resolve local target IP addresses:
0
(default): reply for any local target IP address, configured on any interface
1
reply only if the target IP address is local address configured on the incoming interface
2
reply only if the target IP address is local address configured on the incoming interface and both with the sender's IP address are part from same subnet on this interface
3
do not reply for local addresses configured with scope host, only resolutions for global and link addresses are replied
4-7
reserved
8
do not reply for all local addresses
The max value from conf/{all,interface}/arp_ignore is used when ARP request is received on the {interface}

lmtwl

回复 2# Riet

有2 的
   配合arp_filter 是能解决的。
  arp_announce 和arp_ignore  是对更加详细的 控制arp响应。配合这两个参数在这种机房拓扑的情况下解决了




   

Riet

回复 4# lmtwl


    具体参数设的多少能说明下么。