Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
Hi,
I have a dual port NIC, and I would like to run ping from port A (eth2) to port B (eth3) on same NIC card, using Linux RH5.3 I run:
ping -I eth2 <eth3-ip>
and I don't receive and pong.
It appears that when an ARP request received on eth3 (I used tcpdump) the system decides not to answer the ARP request, apparently because it's sent from a local IP and it doesn't allow you to "query yourself".
Any ideas how can I make this work? I want to test connectivity between port A and port B (not necessarily ping), how can I do that?
Thats some wierd behavior, just tested it myself... the only thing I noticed was that it was being logged as a martian, maybe there was no response because it thought the packet was spoofed ?
Thanks kbp,
Yeah it's odd, I also think it's kind of IP layer security that prevents the ARP modules from answering the ARP request. I tried to disable all security services (firewall, iptables, selinux, sysctl) but didn't succeed to make it work. I even tried to trick the ARP table and set a manual entry for port B so the ping will not initiate ARP request (and will send ICMP echo directly) but the arp table won't let me set an entry of an IP that I own.
You could try mucking about with kernel/network tuning stuff in /etc/sysctl.conf, I thought it might have been source routing related. I had a little play but didnt have that much time available, good luck
kbp, already tried playing with sysctl, it didn't help.
TimothyEBaldwin, that would work, but I wanted to show a real connection like ping-pong (or other application) rather than sniffing packets on port B.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.