VPN over IPVS with direct routing method

["Valeriy V. Peshkoff" <simps@xxxxxxxxxx>]

Hello!

I try to use IPVS under Debian to balance VPN connections (PPTPD) with 
direct routing method:
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.18.247:1723 rr
  -> lnrealserver3:1723           Route    1      0          0
  -> lnrealserver2:1723           Route       1      0          0

TCP 1723 works well, but I've got problems with GRE (proto 47) - 
Director generate ICMP error:
icmp 65: 192.168.18.247 protocol 47 unreachable

After that I use NAT method:

lndirector:~# ipvsadm -l
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.18.247:1723 rr
  -> lnrealserver3:1723           Masq    1      0          0
  -> lnrealserver2:1723           Masq    1      0          0

...  and all works fine


Do you have any ideas for non TCP/UPD protocols with TCP in the same TCP 
session?
From MAN 8 ipvsadm:

Supported features include two protocols (TCP and UDP) ...