I am handling 34 Debian servers. Two of these are diskful machines (which boot from their HDs), the remaining 32 are PXE clients without disks.
The two machines with disks are called uni01 and uni02. uni01 sends a single system image via NFS to the nodes that do network booting (it also runs DHCP + TFTP).
The network is a class A subnet (mask 255.255.252.0). Problem is, one specific node (uni19) cannot contact uni02. They're in the same subnet, the other hosts can connect just fine, except this one.
root@uni19:~# traceroute uni02 traceroute to uni02 (10.248.212.216), 30 hops max, 60 byte packets 1 uni19 (10.248.212.255) 2997.791 ms !H 2997.789 ms !H 2997.784 ms !H
However arping works for uni02:
root@uni02:/home/einar# arping uni19 ARPING 10.248.212.255 60 bytes from 10:1f:74:2c:78:aa (10.248.212.255): index=0 time=172.946 usec 60 bytes from 10:1f:74:2c:78:aa (10.248.212.255): index=1 time=208.391 usec
It doesn't for uni19:
root@uni19:~# arping uni02 ARPING 10.248.212.216 ^C --- 10.248.212.216 statistics --- 4 packets transmitted, 0 packets received, 100% unanswered (0 extra)
root@uni19:~# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default uni01 0.0.0.0 UG 0 0 0 eth0 10.248.212.0 * 255.255.252.0 U 0 0 0 eth0 root@uni02:~# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default uni01 0.0.0.0 UG 0 0 0 eth0.682 10.248.212.0 * 255.255.252.0 U 0 0 0 eth0.682 10.248.216.0 10.248.212.1 255.255.255.0 UG 0 0 0 eth0.682 10.248.217.0 10.248.212.1 255.255.255.0 UG 0 0 0 eth0.682
uni01 and uni02 use specific interfaces for a VLAN, but all the other hosts have been switched to the same VLAN to be able to communicate (in fact, also uni01 is on the same VLAN, but all serers are able to PXE boot).
What can I do to troubleshoot this? I already confirmed there are no firewalls up.