Skip to Main Content

Infrastructure Software

Announcement

For appeals, questions and feedback about Oracle Forums, please email oracle-forums-moderators_us@oracle.com. Technical questions should be asked in the appropriate category. Thank you!

Can only ping one of two interfaces

User51642 Yong HuangMay 10 2019 — edited May 20 2019

My test server has two network interfaces:

[root@dmt1db01 ~]# ip a s bondeth0

11: bondeth0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP

    link/ether 90:e2:ba:52:be:18 brd ff:ff:ff:ff:ff:ff

    inet 10.111.92.80/25 brd 10.111.92.127 scope global bondeth0

...

[root@dmt1db01 ~]# ip a s eth0

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000

    link/ether 00:10:e0:3e:6a:7c brd ff:ff:ff:ff:ff:ff

    inet 10.111.63.172/23 brd 10.111.63.255 scope global eth0

I can ping from my desktop PC to 10.111.92.80 (IP of bondeth0) but not 10.111.63.172 (eth0). On the server, `tcpdump' shows that when ICMP ping packets come in to the eth0 IP from the PC, the server cannot reply after receiving them (note missing "echo reply" packets in the return direction, which would be shown if pinging the bondeth0 IP):

[root@dmt1db01 ~]# tcpdump -n icmp -i eth0

tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes

16:25:26.762198 IP 172.18.38.126 > 10.111.63.172: ICMP echo request, id 1, seq 143, length 40

16:25:31.760500 IP 172.18.38.126 > 10.111.63.172: ICMP echo request, id 1, seq 144, length 40

...

At first I thought it had the same cause as the fact that I could not ping from the server back to the PC using the eth0 source interface (I *was* able to ping back without speficying source interface or specifying bondeth0):

[root@dmt1db01 ~]# ping -I eth0 172.18.38.126

PING 172.18.38.126 (172.18.38.126) from 10.111.63.172 eth0: 56(84) bytes of data.

^C

Then I checked our similarly-configured production server where everything is fine. It had the same "problem": `ping -I eth0 <my PC>' does not work. So what else can I check? The routing table on this box, if it matters, is:

[root@dmt1db01 ~]# route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

0.0.0.0         10.111.92.1     0.0.0.0         UG    0      0        0 bondeth0

192.168.8.0     0.0.0.0         255.255.252.0   U     0      0        0 ib0

192.168.8.0     0.0.0.0         255.255.252.0   U     0      0        0 ib1

I messed with it a bit, adding and deleting some static routes. It made no difference.

Thank you!

This post has been answered by User51642 Yong Huang on May 20 2019
Jump to Answer
Comments
Post Details
Added on May 10 2019
4 comments
1,900 views