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.