I'm sorry for the delay, but we had to do a deliverable in this date, and it was imposible to answer before.

>Could you try again after runing:
>ulimit -c unlimited   #  you need bash for this
>ser -f  ser.cfg -w /tmp/
The parameter "unlimited" already was in this node, so I think this is not the problem.

The scenario used in our test is the following:
- There are two user terminals that are communicated by SIP Communicator program. The INVITE message (problematic paquet)  travels through the nodes until it arrive at the Proxy node. In this node is the problem with the core shown in my previous message. We have MIPv6 in our scenario. In our case, we use mipv6-2.0.2 from http://www.mobile-ipv6.org/ . We have ubuntu with kernel 2.6.16.24

Next, i'll show you the configuration file in the Proxy node:
******************************************************************
#
# P-CSCF
#

# ----------- global configuration parameters ------------------------

check_via=no    # (cmd. line: -v)
dns=yes           # (cmd. line: -r)
rev_dns=yes      # (cmd. line: -R)
fifo="/tmp/ser_fifo"
listen="pcscf"

# ------------------ module loading ----------------------------------

loadmodule "/usr/lib/ser/modules/sl.so"
loadmodule "/usr/lib/ser/modules/tm.so"
loadmodule "/usr/lib/ser/modules/rr.so"
loadmodule "/usr/lib/ser/modules/maxfwd.so"
loadmodule "/usr/lib/ser/modules/textops.so"
loadmodule "/usr/lib/ser/modules/xlog.so"

# ----------------- setting module-specific parameters ---------------

# -- rr params --
# add value to ;lr param to make some broken UAs happy
modparam("rr", "enable_full_lr", 1)

# -------------------------  request routing logic -------------------

# main routing logic

route{

    # initial sanity checks -- messages with
    # max_forwards==0, or excessively long requests
    if (!mf_process_maxfwd_header("10")) {
        sl_send_reply("483","Too Many Hops");
        break;
    };
    if (msg:len > max_len ) {
        sl_send_reply("513", "Message too big");
        break;
    };

    if (method=="REGISTER") {
        # Append the Path header
        # FIXME: "Require" and "Supported" issues
        append_hf("Path: <sip:term@pcscf.domainA.ammi.dit.upm.es;lr>\r\n");
        append_hf("Require: path\r\n");
    };

    # -----------------------------------------------------------------
    # Loose Route Section
    # -----------------------------------------------------------------
 
    if (method != "REGISTER") {
        record_route();
    };
         
    if (loose_route()) {
        route(1);
        break;
    };

    # forward to current uri now; use stateful forwarding; that
    # works reliably even if we forward from TCP to UDP
    route(1);
}

route[1] {
    # -----------------------------------------------------------------
    # Default Message Handler
    # -----------------------------------------------------------------

    if (!t_relay()) {
        sl_reply_error();
    };
}
****************************************************************
In the next message i'll show the packet INVITE that produces the error becuase. Otherwise, the message would be very big (>40 KB) and it would not be shown.

Thanks.