Re: [NSE] errors: path-mtu, dns-cache-snoop, and firewalk

[Kris Katterjohn <katterjohn () gmail com>]

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On 10/18/2010 05:24 PM, Ron wrote:
> Just some error I'm seeing on a larger scan.
>
>
> ./scripts/path-mtu.nse:332: error while sending: Message too long (errno 90)
> stack traceback:
>         [C]: in function 'ip_send'
>         ./scripts/path-mtu.nse:332: in function <./scripts/path-mtu.nse:292>
>         (tail call): ?

This will happen when Nmap cannot determine the MTU for the outgoing
interface.  path-mtu assumes errors from ip_send() are due to this (not that
it matters much) and drops to another MTU level and continues.

Does "nmap --iflist" show the correct MTU for the interface on the source machine?

This is my first thought since I know this behavior can occur this way, so let
me know and I'll think more on it if you see Nmap knows the correct MTU but
path-mtu is still causing this error.

Also, does the problem occur on a small scan?  If this is the problem, it
should cause an error for any path-mtu run over that interface (not just on
large scans).

> Ron

Thanks,
Kris Katterjohn

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