I have OBSD 3.4 running squid and using WCCP.

tcpdump shows that GRE is being replied as unreachable. Is anyone able to
tell me why?


22:44:09.860757 openbsd.2048 > cisco837.2048: udp 52
22:44:09.863149 cisco837.2048 > openbsd.2048: udp 64
22:44:20.882618 openbsd.2048 > cisco837.2048: udp 52
22:44:20.885026 cisco837.2048 > openbsd.2048: udp 64
22:44:26.461056 gre-proto-0x883e (gre encap)
22:44:26.461119 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:26.462368 gre-proto-0x883e (gre encap)
22:44:26.462395 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:26.463645 gre-proto-0x883e (gre encap)
22:44:26.463663 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:26.465103 gre-proto-0x883e (gre encap)
22:44:26.465120 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:26.466374 gre-proto-0x883e (gre encap)
22:44:26.466397 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:26.467653 gre-proto-0x883e (gre encap)
22:44:26.467670 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:26.469148 gre-proto-0x883e (gre encap)
22:44:26.469167 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:26.470423 gre-proto-0x883e (gre encap)
22:44:26.470440 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:26.471696 gre-proto-0x883e (gre encap)
22:44:26.471716 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:31.459717 gre-proto-0x883e (gre encap)
22:44:31.459802 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
22:44:31.871685 openbsd.2048 > cisco837.2048: udp 52
22:44:31.873766 cisco837.2048 > openbsd.2048: udp 64


--
Cheers,
Jason

Note: Use ROT13 to decipher my email address

Jason wrote:
> I have OBSD 3.4 running squid and using WCCP.
>
> tcpdump shows that GRE is being replied as unreachable. Is anyone able to
> tell me why?
>
>
> 22:44:09.860757 openbsd.2048 > cisco837.2048: udp 52
> 22:44:09.863149 cisco837.2048 > openbsd.2048: udp 64
> 22:44:20.882618 openbsd.2048 > cisco837.2048: udp 52
> 22:44:20.885026 cisco837.2048 > openbsd.2048: udp 64
> 22:44:26.461056 gre-proto-0x883e (gre encap)
> 22:44:26.461119 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:26.462368 gre-proto-0x883e (gre encap)
> 22:44:26.462395 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:26.463645 gre-proto-0x883e (gre encap)
> 22:44:26.463663 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:26.465103 gre-proto-0x883e (gre encap)
> 22:44:26.465120 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:26.466374 gre-proto-0x883e (gre encap)
> 22:44:26.466397 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:26.467653 gre-proto-0x883e (gre encap)
> 22:44:26.467670 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:26.469148 gre-proto-0x883e (gre encap)
> 22:44:26.469167 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:26.470423 gre-proto-0x883e (gre encap)
> 22:44:26.470440 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:26.471696 gre-proto-0x883e (gre encap)
> 22:44:26.471716 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:31.459717 gre-proto-0x883e (gre encap)
> 22:44:31.459802 openbsd > cisco837: icmp: openbsd protocol 47 unreachable
> 22:44:31.871685 openbsd.2048 > cisco837.2048: udp 52
> 22:44:31.873766 cisco837.2048 > openbsd.2048: udp 64
>
>
http://www.openbsd.org/cgi-bin/man.c...86&format=html
gre - encapsulating network device

SYNOPSIS
pseudo-device gre [count]

NOTE
GRE, WCCPv1, and MobileIP are enabled with the following sysctl(3)
vari-
ables respectively in /etc/sysctl.conf:

net.inet.gre.allow Allow GRE packets in and out of the system.

net.inet.gre.wccp Allow WCCPv2-style GRE packets into the system
(depends on the above).

net.inet.mobileip.allow
Allow MobileIP packets in and out of the
system.

DESCRIPTION
The gre network interface allows tunnel construction using the
Cisco GRE
or the Mobile-IP (RFC 2004) encapsulation protocols.

This driver currently supports the following modes of operation:

GRE encapsulation (IP protocol number 47).