[lug] Weird mail/firewall problem

[Chip Atkinson]

Is there a tool that allows you to send different kind of packets across a
network?  In a sense, kind of a firewall tester.  Is this perhaps what
satan and other network tools do?  I've never really played with them
(yet).

It would be nice to have something that says "can't get icmp must fragment
but don't fragment bit is set messages.  May cause problems"

CHip


 On Wed, 13 Feb 2002, D. Stimits wrote:

> rm at fabula.de wrote:
> ...snip...
> > > Just for kicks, maybe get your
> > > failed email test on an interface, then use ifconfig to set to something
> > > small on the interface itself, say 296 (power of 2 plus 40 assuming tcp
> > > header), and see if it then gets through. Or maybe some other error
> > > occurs.
> >
> > That's a good diagnosis technique, indeed. Hmm, just to throw it in:
> > you can also use 'tracepath':
>
> Interesting tool, I like it. The man page didn't explain what asymm
> means, hopefully someone here knows?
>
> >
> > |  www:/home/ralf# tracepath www.zeit.de/80
> > |  1?: [LOCALHOST]      pmtu 1500
> > |  1?: 212.18.192.129
> > |  2?: 212.18.192.22
> > |  3?: 212.88.129.142
> > |  4?: 213.248.68.101
> > |  5?: 193.45.9.81
> > |  6?: 213.248.68.90
> > |  7?: 80.81.192.190    asymm  8
> > |  8?: 212.38.193.205
> > |  9?: 212.38.192.189   asymm  7
> > | 10?: 212.38.221.33    asymm  6
> > | 11?: 212.38.221.102   asymm  8
> > | 12?: 194.64.3.101     asymm  9
> > | 13?: 194.64.3.45      asymm  8
> > | 14?: 194.163.251.75   asymm  9
> > | 15:  194.163.254.175  asymm 10  23ms reached
> > |      Resume: pmtu 1500 hops 15 back 10
> > |
> >
> > Same test from my firewall (attached to a DSL line):
> >
> > | barrique:/home/moep# tracepath www.zeit.de/80
> > |  1?: [LOCALHOST]      pmtu 1492
> > |  1?: 217.5.98.41      asymm  5
> > |  2?: 217.237.153.42
> > |  3?: 62.154.18.46     asymm  8
> > |  4?: 194.64.3.30      asymm  8
> > |  5?: 195.180.3.209    asymm  8
> > |  6?: 194.163.251.75   asymm  8
> > |  7:  194.163.254.175  asymm  8 162ms reached
> > |      Resume: pmtu 1492 hops 7 back 8
> > |
> >
> > another debuging tool would be 'hping'.
>
> This one (hping) I don't have, I presume it gives ping information with
> some extra data?
>
> D. Stimits, stimits at idcomm.com
>
> >
> >   Ralf
> ...snip...
> _______________________________________________
> Web Page:  http://lug.boulder.co.us
> Mailing List: http://lists.lug.boulder.co.us/mailman/listinfo/lug
>