icmp requset packet send from eth0 and icmp reply packet receive from eth1,why linux ingore it

gbcbooks · 09-22-2017, 11:52 PM

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as the topology ,

i use "ping -I eth1 9.9.9.9 " on JP , and watch tcpdump -i eth0 "icmp && host 9.9.9.9",

tcpdump was able to capture icmp reply packet , but ping was ingoring it .

i have enable net.conf.ipv4.ip_forward=1 and net.conf.ipv4.all.rp_filter=0

any one can tell me what is going on ?

lazydog · 09-23-2017, 08:32 AM

Firewall running?

gbcbooks · 09-25-2017, 12:57 PM

firewall was running , but firewall rule did not drop the packet . and i did not find any log about the icmp in the /var/log/kern.log file.

lazydog · 09-25-2017, 01:38 PM

Look at your routing table you might find that packets are not traversing the way you think they should.

camp0 · 09-25-2017, 04:38 PM

Put your firewall rules and your routing table helps

voleg · 09-26-2017, 08:16 AM

Using IP addresses from same subnet usually cause that.
If you need more IP from same subnet, use IP alias.
If you need redundancy or throughput by using two cards, use bond.