I'm running SuSE 9.2, with an ISDN internet connection, managed by kinternet. I can manually dial-in using kinternet. I've checked the appropriate box in YAST for dial-on-demand. However, dial on demand is not working. When I'm offline and perform an action that requires internet access, I get "Martian source" system messages, and a stack trace.

For example:

> ping 1.2.3.4
PING 1.2.3.4 (1.2.3.4) 56(84) bytes of data.
Segmentation fault
>

with the following syslog message:

Apr 21 16:02:50 ben kernel: martian source 1.2.3.4 from 0.0.0.0, on dev lo
Apr 21 16:02:50 ben kernel: ll header: <1>Unable to handle kernel NULL pointer dereference at virtual address 00000000

{and the subsequent stack trace can be found at the end of this message}

I understand that martian addresses are ones which an IP router can immediately discard as erroneous, and for which no further action (other than logging) should be taken. So I'm assuming that 0.0.0.0 is being treated by my machine as a martian address. ( The above happens if you change 1.2.3.4 to any other address - so there's nothing martian about that).

However, my ISP issues dynamic IP addresses, and I was under the impression that 0.0.0.0 was used as a source address in cases where the originating application (ping, for example) cannot determine the source address (e.g. dynamically allocated IP addresses, with an offline, dial-on-demand link to the internet). In which case, 0.0.0.0 should not be treated as a martian source address.

So, is there some mis-configuration that is causing the 0.0.0.0 to be treated erroneously as a martian source address?
Or perhaps my understanding is flawed?

Or is the martian source address completely unrelated to the NULL pointer that follows?

But what's causing the kernel null pointer dereference? Is this a software bug? The full syslog output, including the stack trace follows.

Thanks in anticipation for your help.

Matt.

SYSLOG -------------------------------------------------
Apr 21 16:02:50 ben kernel: martian source 1.2.3.4 from 0.0.0.0, on dev lo
Apr 21 16:02:50 ben kernel: ll header: <1>Unable to handle kernel NULL pointer d
ereference at virtual address 00000000
Apr 21 16:02:50 ben kernel: printing eip:
Apr 21 16:02:50 ben kernel: c02ab856
Apr 21 16:02:50 ben kernel: *pde = 00000000
Apr 21 16:02:50 ben kernel: Oops: 0000 [#11]
Apr 21 16:02:50 ben kernel: Modules linked in: usbserial parport_pc lp parport nvram ipt_TOS ip6t_LOG ip6t_limit ipt_LOG ipt_limit ipt_pkttype speedstep_lib freq_table thermal processor fan button battery ac snd_pcm_oss snd_mixer_oss snd_via82xx snd_ac97_codec snd_pcm snd_timer snd_page_alloc gameport snd_mpu401_uart snd_rawmidi snd_seq_device snd soundcore ip6t_state ip6_conntrack ipt_state ip6t_REJECT ipt_REJECT iptable_mangle iptable_filter ip6table_mangle ip_nat_ftp iptable_nat ip_conntrack_ftp ip_conntrack ip_tables ip6table_filter ip6_tables ipv6 hisax crc_ccitt isdn slhc ds yenta_socket pcmcia_core binfmt_misc subfs nls_utf8ntfs edd ehci_hcd sk98lin joydev sg st sr_mod ide_cd cdrom via_agp agpgart uhci_hcd evdev dm_mod usbcore reiserfs sata_via libata sd_mod scsi_mod
Apr 21 16:02:50 ben kernel: CPU: 0
Apr 21 16:02:50 ben kernel: EIP: 0060:[<c02ab856>] Not tainted VLI
Apr 21 16:02:50 ben kernel: EFLAGS: 00210246 (2.6.8-24-default 20041006091623)
Apr 21 16:02:50 ben kernel: EIP is at ip_route_input_slow+0x876/0x8d0
Apr 21 16:02:50 ben kernel: eax: 00000000 ebx: 00000000 ecx: ccd37a24 edx: c0347cfd
Apr 21 16:02:50 ben kernel: esi: 00000000 edi: 00000000 ebp: cde921a0 esp: ccd37a24
Apr 21 16:02:50 ben kernel: ds: 007b es: 007b ss: 0068
Apr 21 16:02:50 ben kernel: Process ping (pid: 15891, threadinfo=ccd36000 task=d3b8a000)
Apr 21 16:02:50 ben kernel: Stack: 00000000 ffffffea 000015f6 00000000 00000000037f6a0 ce48d5a0 04030201
Apr 21 16:02:50 ben kernel: 00000000 cde921a0 00000000 00000000 0000000104030201 00000000 00000000
Apr 21 16:02:50 ben kernel: 00000000 00000000 00000000 00000000 0000000000000000 00000000 00000000
Apr 21 16:02:50 ben kernel: Call Trace:
Apr 21 16:02:50 ben kernel: [<c02ab8e2>] ip_route_input+0x32/0x170
Apr 21 16:02:50 ben kernel: [<c029d43f>] ip_route_me_harder+0x11f/0x2c0
Apr 21 16:02:50 ben kernel: [<c02b2c70>] ip_finish_output2+0x0/0x190
Apr 21 16:02:50 ben kernel: [<f93e3a30>] ip_nat_out+0xc0/0x160 [iptable_nat]
Apr 21 16:02:50 ben kernel: [<c029cdae>] nf_iterate+0x5e/0xa0
Apr 21 16:02:50 ben kernel: [<c02b2c70>] ip_finish_output2+0x0/0x190
Apr 21 16:02:50 ben kernel: [<c02b2c70>] ip_finish_output2+0x0/0x190
Apr 21 16:02:50 ben kernel: [<c029d0c2>] nf_hook_slow+0x52/0xd0
Apr 21 16:02:50 ben kernel: [<c02b2c70>] ip_finish_output2+0x0/0x190
Apr 21 16:02:50 ben kernel: [<c02b02c0>] ip_dst_output+0x0/0x60
Apr 21 16:02:50 ben kernel: [<c02b0670>] ip_finish_output+0xe0/0x1e0
Apr 21 16:02:50 ben kernel: [<c02b2c70>] ip_finish_output2+0x0/0x190
Apr 21 16:02:50 ben kernel: [<c02b02c0>] ip_dst_output+0x0/0x60
Apr 21 16:02:50 ben kernel: [<c02b095f>] ip_output+0x8f/0xf0
Apr 21 16:02:50 ben kernel: [<c02b02e5>] ip_dst_output+0x25/0x60
Apr 21 16:02:50 ben kernel: [<c029d139>] nf_hook_slow+0xc9/0xd0
Apr 21 16:02:50 ben kernel: [<c02b280c>] ip_push_pending_frames+0x39c/0x460
Apr 21 16:02:50 ben kernel: [<c02b02c0>] ip_dst_output+0x0/0x60
Apr 21 16:02:50 ben kernel: [<c02ac26a>] __ip_route_output_key+0xba/0xe0
Apr 21 16:02:50 ben kernel: [<c02ccef4>] raw_sendmsg+0x3e4/0x430
Apr 21 16:02:50 ben kernel: [<c02a9c02>] rt_intern_hash+0x2b2/0x3b0
Apr 21 16:02:50 ben kernel: [<c02d4e09>] inet_sendmsg+0x39/0x50
Apr 21 16:02:50 ben kernel: [<c028c427>] sock_sendmsg+0xe7/0x120
Apr 21 16:02:50 ben kernel: [<c022946d>] n_tty_receive_buf+0x14d/0xb50
Apr 21 16:02:50 ben kernel: [<c013a1a6>] buffered_rmqueue+0xf6/0x1d0
Apr 21 16:02:50 ben kernel: [<c011aa20>] autoremove_wake_function+0x0/0x30
Apr 21 16:02:50 ben kernel: [<c01d3119>] copy_from_user+0x29/0x50
Apr 21 16:02:50 ben kernel: [<c029186a>] verify_iovec+0x2a/0x80
Apr 21 16:02:50 ben kernel: [<c028dc4a>] sys_sendmsg+0x13a/0x1b0
Apr 21 16:02:50 ben kernel: [<c01440fa>] do_no_page+0x18a/0x270
Apr 21 16:02:50 ben kernel: [<c022b822>] pty_write+0xf2/0x130
Apr 21 16:02:50 ben kernel: [<c0144392>] handle_mm_fault+0xf2/0x120
Apr 21 16:02:50 ben kernel: [<c011799e>] do_page_fault+0x1be/0x56c
Apr 21 16:02:50 ben kernel: [<c028e2b0>] sock_setsockopt+0x70/0x4c0
Apr 21 16:02:50 ben kernel: [<c0145a40>] __do_mmap_pgoff+0x410/0x700
Apr 21 16:02:50 ben kernel: [<c01d30e7>] copy_to_user+0x27/0x30
Apr 21 16:02:50 ben kernel: [<c022b338>] n_tty_ioctl+0x88/0x330
Apr 21 16:02:50 ben kernel: [<c022b2b0>] n_tty_ioctl+0x0/0x330
Apr 21 16:02:50 ben kernel: [<c028def1>] sys_socketcall+0x71/0x1b0
Apr 21 16:02:50 ben kernel: [<c011fe95>] sys_gettimeofday+0x25/0x60
Apr 21 16:02:50 ben kernel: [<c0105c69>] sysenter_past_esp+0x52/0x79
Apr 21 16:02:50 ben kernel: Code: 58 e9 1f f9 ff ff 68 03 69 33 c0 e8 e5 11 e7 ff 58 8b 84 24 f4 00 00 00 66 8b 50 62 89 d0 46 25 ff ff 00 00 43 39 c6 7d cd 31c0 <8a> 03 50 68 c9 fe 32 c0 e8 bd 11 e7 ff 8b 8c 24 fc 00 00 00 66