Hello all, I'm still wondering is it ip_conntrack_proto_gre related problem? This PC is used as PPTP-server (up to 80-100 concurrent connections) and as NAT-server. There is of course some natted GRE-connections also. All connections is from (and to) untrusted users. Here is a output of ksymoops: ksymoops 2.4.9 on i686 2.4.27. Options used -V (default) -k /proc/ksyms (default) -l /proc/modules (default) -o /lib/modules/2.4.27/ (default) -m /usr/src/linux/System.map (default) Warning: You did not tell me where to find symbol information. I will assume that the log matches the kernel and modules that are running right now and I'll use the default options above for symbol resolution. If the current kernel and/or modules do not match the log, you can get more accurate output by telling me the kernel version and where to find map, modules, ksyms etc. ksymoops -h explains the options. Warning (compare_maps): ksyms_base symbol IO_APIC_get_PCI_irq_vector_R__ver_IO_APIC_get_PCI_irq_vector not found in System.map. Ignoring ksyms_base entry *pde = 00000000 Oops: 0002 CPU: 0 EIP: 0010:[<e0a232b8>] Not tained Using defaults from ksymoops -t elf32-i386 -a i386 EFLAGS: 10282 eax: d4a47bf8 ebx: d99f1180 ecx: cefd1480 edx: 00000000 esi: d526e080 edi: 00000000 ebp: 00000046 esp: c02a7f04 ds: 0018 es: 0018 ss: 0018 Process swapper (pid: 0, stackpage=c02a7000) Stack: e09f3939 d526e080 e09f3e16 d99f1180 e09f3d04 d526e080 e09f3920 fffffffe e09f3e79 d526e080 d526e080 c012048b d526e080 dffeb200 c02a7f3c c02a7f3c 00000000 c02c7a80 fffffffe 00000046 c011cc42 c011cb56 00000000 00000001 Call Trace: [<e09f3939>] [<e09f3e16>] [<e09f3d04>] [<e09f3e20>] [<e0ef3e79>] [<c012048b>] [<c011cc42>] [<c011cb56>] [<c011c995>] [<c01089da>] [<c01052c0>] [<c010ade8>] [<c01052c0>] [<c01052e3>] [<c0105372>] [<c0105000>] Code: 89 02 c7 41 04 00 00 00 00 c7 01 00 00 00 00 8b 83 80 00 00 >>EIP; e0a232b8 <[ip_conntrack_proto_gre]ip_ct_gre_keymap_destroy+88/c0> <===== >>eax; d4a47bf8 <_end+14742374/206247dc> >>ebx; d99f1180 <_end+196eb8fc/206247dc> >>ecx; cefd1480 <_end+eccbbfc/206247dc> >>esi; d526e080 <_end+14f687fc/206247dc> >>esp; c02a7f04 <init_task_union+1f04/2000> Trace; e09f3939 <[ip_conntrack]ip_ct_find_proto+19/40> Trace; e09f3e16 <[ip_conntrack]destroy_conntrack+106/110> Trace; e09f3d04 <[ip_conntrack]clean_from_lists+54/60> Trace; e09f3e20 <[ip_conntrack]death_by_timeout+0/60> Trace; e0ef3e79 <END_OF_CODE+2e35d6/????> Trace; c012048b <timer_bh+17b/3a0> Trace; c011cc42 <bh_action+22/40> Trace; c011cb56 <tasklet_hi_action+46/70> Trace; c011c995 <do_softirq+95/a0> Trace; c01089da <do_IRQ+9a/a0> Trace; c01052c0 <default_idle+0/40> Trace; c010ade8 <call_do_IRQ+5/d> Trace; c01052c0 <default_idle+0/40> Trace; c01052e3 <default_idle+23/40> Trace; c0105372 <cpu_idle+52/70> Trace; c0105000 <_stext+0/0> Code; e0a232b8 <[ip_conntrack_proto_gre]ip_ct_gre_keymap_destroy+88/c0> 00000000 <_EIP>: Code; e0a232b8 <[ip_conntrack_proto_gre]ip_ct_gre_keymap_destroy+88/c0> <===== 0: 89 02 mov %eax,(%edx) <===== Code; e0a232ba <[ip_conntrack_proto_gre]ip_ct_gre_keymap_destroy+8a/c0> 2: c7 41 04 00 00 00 00 movl $0x0,0x4(%ecx) Code; e0a232c1 <[ip_conntrack_proto_gre]ip_ct_gre_keymap_destroy+91/c0> 9: c7 01 00 00 00 00 movl $0x0,(%ecx) Code; e0a232c7 <[ip_conntrack_proto_gre]ip_ct_gre_keymap_destroy+97/c0> f: 8b 83 80 00 00 00 mov 0x80(%ebx),%eax 2 warnings issued. Results may not be reliable. -- Loaded modules: bsd_comp 4216 0 (autoclean) ppp_deflate 3320 11 (autoclean) zlib_inflate 18596 0 (autoclean) [ppp_deflate] zlib_deflate 18936 0 (autoclean) [ppp_deflate] ppp_async 6624 91 (autoclean) ppp_generic 16964 273 (autoclean) [bsd_comp ppp_deflate ppp_async] slhc 4768 14 (autoclean) [ppp_generic] ipt_MASQUERADE 1336 2 (autoclean) ipt_limit 920 1 (autoclean) ipt_string 1724 1 (autoclean) ipt_ULOG 4612 2 (autoclean) ipt_LOG 3936 3 (autoclean) iptable_filter 1772 1 (autoclean) ipt_MARK 792 1 (autoclean) iptable_mangle 2200 1 (autoclean) ip_nat_proto_gre 2180 0 (unused) ip_conntrack_pptp 7281 1 (autoclean) ip_nat_pptp 4620 0 (unused) ip_conntrack_proto_gre 3829 0 [ip_conntrack_pptp ip_nat_pptp] ip_conntrack_ftp 4112 1 (autoclean) ip_nat_ftp 3024 0 (unused) iptable_nat 17646 4 [ipt_MASQUERADE ip_nat_proto_gre ip_nat_pptp ip_nat_ftp] ip_tables 12416 11 [ipt_MASQUERADE ipt_limit ipt_string ipt_ULOG ipt_LOG iptable_filter ipt_MARK iptable_mangle iptable_nat] ip_conntrack 20484 3 [ipt_MASQUERADE ip_conntrack_pptp ip_nat_pptp ip_conntrack_proto_gre ip_conntrack_ftp ip_nat_ftp iptable_nat] dummy 984 0 (unused) e1000 74992 3 e100 32556 1 Any help would be greatly appreciated. -- wbr, Oleg.