And the last bits of information which seem to be necessary for help:
gw8.domain.com (X.Y.151.89) at 00:1A:30:38:90:00 [ether] on eth1
? (10.10.156.193) at 00:1A:30:38:A8:00 [ether] on eth0
alpha.domain.com (X.Y.152.160) at * PERM PUP on eth1
alpha.domain.com (X.Y.152.160) at * PERM PUP on eth0
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
X.Y.152.160  0.0.0.0         255.255.255.255 UH    0      0        0 venet0
X.Y.151.88   0.0.0.0         255.255.255.248 U     0      0        0 eth1
10.10.156.192   0.0.0.0         255.255.255.192 U     0      0        0 eth0
X.Y.152.0    0.0.0.0         255.255.255.0   U     0      0        0 eth1
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0 eth1
10.0.0.0        10.10.156.193   255.0.0.0       UG    0      0        0 eth0
0.0.0.0         X.Y.151.89   0.0.0.0         UG    0      0        0 eth1
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
192.0.2.0       0.0.0.0         255.255.255.0   U     0      0        0 venet0
169.254.0.0     0.0.0.0         255.255.0.0     U     0      0        0 venet0
0.0.0.0         192.0.2.1       0.0.0.0         UG    0      0        0 venet0
If anyone has any suggestions, please make sure to type out the code as well, as I might not really know what to do otherwise.