1st hop in traceroute from a OpenVZ container shows private interface IP[Proxmox 1.6]

[alamar]

proxmox 1.6
From within OpenVZ containers I see the private space (rfc 1918) address
of the drbdlink interface as first hop and not of my publicly connected interface (eth0/vmbr0)

From within container a traceroute looks like this:

/# traceroute -n www.heise.de
traceroute to www.heise.de (193.99.144.85), 30 hops max, 40 byte packets
1 10.0.23.2 0.033 ms 0.007 ms 0.007 ms
2 217.x.99.13 2.206 ms 2.243 ms 2.285 ms

why is the first hope (the hostnode) displayed with the private address of drbdlink interface?
(I would expect it to be 217.x.50.8 at least that's what I want)

ip addr show

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000
link/ether 00:25:90:1d:30:9e brd ff:ff:ff:ff:ff:ff
inet6 fe80::225:90ff:fe1d:309e/64 scope link
valid_lft forever preferred_lft forever
3: eth3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
link/ether 00:1b:21:7b:4e:46 brd ff:ff:ff:ff:ff:ff
4: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
link/ether 00:25:90:1d:30:9f brd ff:ff:ff:ff:ff:ff
5: drbdlink: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:1b:21:7b:4e:47 brd ff:ff:ff:ff:ff:ff
inet 10.0.23.2/24 brd 10.0.23.255 scope global drbdlink
inet 10.0.23.12/24 brd 10.0.23.255 scope global secondary drbdlink:0
inet6 fe80::21b:21ff:fe7b:4e47/64 scope link
valid_lft forever preferred_lft forever
6: vmbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
link/ether 00:25:90:1d:30:9e brd ff:ff:ff:ff:ff:ff
inet 217.x.50.8/24 brd 217.x.50.255 scope global vmbr0
inet 217.x.50.10/32 brd 217.x.50.138 scope global vmbr0
inet6 fe80::225:90ff:fe1d:309e/64 scope link
valid_lft forever preferred_lft forever
7: venet0: <BROADCAST,POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
link/void


brctl show:
bridge name bridge id STP enabled interfaces
vmbr0 8000.0025901d309e no eth0

ip ro show:

217.x.50.11 dev venet0 scope link
217.x.50.254 dev venet0 scope link
217.x.50.14 dev venet0 scope link
217.x.50.15 dev venet0 scope link
217.x.50.12 dev venet0 scope link
217.x.50.13 dev venet0 scope link
10.0.23.0/24 dev drbdlink proto kernel scope link src 10.0.23.2
217.x.50.0/24 dev vmbr0 proto kernel scope link src 217.x.50.8
default via 217.x.50.1 dev vmbr0

x is always the same.

 

[udo]

Re: 1st hop in traceroute from a OpenVZ container shows private interface IP[Proxmox

proxmox 1.6
From within OpenVZ containers I see the private space (rfc 1918) address
of the drbdlink interface as first hop and not of my publicly connected interface (eth0/vmbr0)

From within container a traceroute looks like this:

/# traceroute -n www.heise.de
traceroute to www.heise.de (193.99.144.85), 30 hops max, 40 byte packets
1 10.0.23.2 0.033 ms 0.007 ms 0.007 ms
2 217.x.99.13 2.206 ms 2.243 ms 2.285 ms

why is the first hope (the hostnode) displayed with the private address of drbdlink interface?
(I would expect it to be 217.x.50.8 at least that's what I want)

...

Hi,
why do you think that? I would say, it's normal to get the hop inside the network.
If i do this from my home (normal machines) i got the same:

traceroute -n www.heise.de
traceroute to www.heise.de (193.99.144.85), 30 hops max, 60 byte packets
 1  192.168.200.1  0.617 ms  0.865 ms  8.640 ms
 2  62.x.64.253  48.562 ms  53.235 ms  59.602 ms

i get also the router-ip and not 62.x.64.20 ... i think this is the right behavior.

Udo

 

[alamar]

Re: 1st hop in traceroute from a OpenVZ container shows private interface IP[Proxmox

Because the drbdlink interface has nothing to do with the way packets travel. (At least I don't see how) And on another machine (no proxmox but openvz) with venet I get a trace like this:

~ $ traceroute -n www.heise.de
traceroute to www.heise.de (193.99.144.85), 30 hops max, 60 byte packets
1 85.x.187.154 0.033 ms 0.015 ms 0.014 ms
2 194.146.118.16 11.098 ms 11.075 ms 11.215 ms