On Tuesday 22 August 2006 11:11, Samuel Korpi wrote: > On 8/18/06, Jeff Dike <[EMAIL PROTECTED]> wrote: > > On Fri, Aug 18, 2006 at 09:40:03AM -0400, Charles Wright wrote: > > > However the guest can't ping itself: > > > [EMAIL PROTECTED] ~]# ping -c 1 192.168.42.2 > > > PING 192.168.42.2 (192.168.42.2) 56(84) bytes of data. > > > > > > --- 192.168.42.2 ping statistics --- > > > 1 packets transmitted, 0 received, 100% packet loss, time 0ms > > > > > > Any suggestions? > > > > Do you have a loopback interface? (I think this probably doesn't > > matter, though) > > Actually, it does matter. I noticed the same weird behaviour until I > configured the loopback interface. Don't know why the loopback device > is required, though. But it seems that when pinging the host itself, > no packets actually leave the host, so there has to be some kind of a > shortcut inside the TCP/IP stack which apparently uses the loopback > device for local pings. > > BR, > > Samuel Korpi
Dunno, but probably "ip" will help you to take a closer look. route, ifconfig and friends run on a sort of emulation with restricted semantics - probably to look at this you'll need the full power of "ip". Quite frankly I do not see anything explaining this _on my system_ (maybe the "local" flag in some routes means "use loopback") # ip rule ls 0: from all lookup local 32766: from all lookup main 32767: from all lookup default # ip route ls table local broadcast 192.168.0.255 dev eth0 proto kernel scope link src 192.168.0.200 broadcast 192.168.1.0 dev eth0 proto kernel scope link src 192.168.1.21 broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1 local 192.168.1.21 dev eth0 proto kernel scope host src 192.168.1.21 local 87.3.96.80 dev ppp0 proto kernel scope host src 87.3.96.80 local 192.168.0.200 dev eth0 proto kernel scope host src 192.168.0.200 broadcast 192.168.0.0 dev eth0 proto kernel scope link src 192.168.0.200 broadcast 192.168.1.31 dev eth0 proto kernel scope link src 192.168.1.21 broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1 local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1 local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1 FYI, "ip route ls table main" or "ip route ls" (which is a short for the former) both show the normal routing table. And with a suitably compiled kernel you can even use netfilter "MARK" values to select the routing table to use (you must add a rule to "ip rule ls" rule table). -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
