Go CCIE Go!! - A Cisco Certified Internetwork Expert

I’ve had this happen to me once and another teammate once. I’ve learned that the second someone has a multicast problem, tell them to fire up tcpdump and paste in the output from the sender. My teammate spent about 2 hours looking at the problem, I heard him complaining so when a different developer with a different application showed up on our doorstep I checked that pretty close to first.
The second time was confusing because SSM was working all over, and normal mcast was working on the same vlan. It turned out to be a bug in some underlying Java nonsense, and the SSM libraries were written by someone else in C.
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> From: joe@affirmedsystems.com > To: gwendel@gmail.com; ccielab@groupstudy.com > Subject: RE: Interesting issue while testing multicast. TTL value from linux box. > Date: Wed, 23 Jul 2008 01:13:44 -0400 > > That is very nice to know, thanks Greg. > > I wonder if this applies to other linux distros as well… > > Or can be changed in the ip*.c & .h files and fixed with a recompile? > > Anyone? > > Thanks, > > Joe > > —–Original Message—– > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Greg > Wendel > Sent: Wednesday, July 23, 2008 12:59 AM > To: Cisco certification > Subject: Interesting issue while testing multicast. TTL value from linux > box. > > While testing a multicast setup I ran into an issue where my test linux box > couldn’t work as a multicast source. > > The problem ended up being the TTL on the multicast ping packets. > Apparently the default behavior on my distro, Centos, is to set the TTL to 1 > on multicast pings. > > I added the -t flag and magically everything worked. > > ping 233.1.1.1 -t 101 > > Hope this helps someone. > > — > Gregory Wendel, CCIE #20179(R&S) > Springfield VA, 22153 > > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html > > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html > > > >
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