It just occurred to me that one could use the extended traceroute on the back end for a Cisco to tweak the source IP but there again, it would not be completely effective unless everyone did this. -Dave David McGaugh wrote:
Tweaking our Looking Glass software by itself would not fix the problem (ours doesn't have this problem anyway). To fix the problem everyone would have to tweak their Looking Glass software since the problem can be seen when someone traceroutes from a peer or 3rd party's Looking Glass into our customer (in the event they weren't receiving the IXP blocks from us).
One better might be to have the Looking Glass participating routers manipulate their source IP address for pings and traceroutes.
Cisco: Router(config)#ip traceroute source-interface ? % Unrecognized command Hmmm...
Router(config)#ip ping source-interface ? % Unrecognized command Hmmm...
Juniper: [edit] Router# set system default-address-selection Hey that works!
Is there a way of doing this on a Cisco?
-Dave
"Sean M. Doran" wrote:
| While on the subject of IXP blocks, we also ended up redistributing the | IXP blocks and sending them to our BGP customers (who do not receive a | default) so that traceroutes and such from Looking Glasses do not break. | They can then choose to filter them as they wish.
This is backwards. Do not break the architecture to fix a broken looking glass (or to work around bad interpretations of real-world traceroute results). Spend a few minutes scripting your looking glass software so that if it sees a well-known target, or an expected real-world result (1918 addresses that YOU are using, with expected ttl-distance), it returns a "sanitized" result to a naive looking glass user.
I wonder if there exists the possibility of a useful (perhaps open source) generalized expert system to interpret traceroute data? "configure; make; make install" is probably even easier than breaking one's filter lists to leak prefixes all over the place.
Sean. (that was a hint. you know who you are.)
-- ------------------------------------------ Dave McGaugh, Internetwork Engineer Electric Lightwave, Inc. E-mail: dmcgaugh@eli.net Office: 360.816.3718 | Fax: 360.816.3297 ------------------------------------------