When you specify a packet size with the ping command it includes the headers in the calculation. I use this command and the df-flag frequently to determine the MTU of tunnels.
On Mon, May 13, 2013 at 9:17 PM, Anthony Kellar <[email protected]>wrote: > I would think that if 1500 is your MTU size...that you could never ping > with the df bit set with a packet size of 1500. Do you not have to account > for the icmp header, ipv4 header, etc? > > Sent from my iPad > > On May 13, 2013, at 11:02 AM, [email protected] wrote: > > > Send CCIE_RS mailing list submissions to > > [email protected] > > > > To subscribe or unsubscribe via the World Wide Web, visit > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > > or, via email, send a message with subject or body 'help' to > > [email protected] > > > > You can reach the person managing the list at > > [email protected] > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of CCIE_RS digest..." > > > > > > Today's Topics: > > > > 1. Re: MTU and Domain groups (Les Waller) > > 2. pim accept-rp (Imran Ali) > > 3. Re: pim accept-rp (Saleh Batouq) > > 4. Proctor Labs (Houssam Chahine) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Sun, 12 May 2013 18:39:05 +0200 > > From: Les Waller <[email protected]> > > To: ccie <[email protected]> > > Subject: Re: [OSL | CCIE_RS] MTU and Domain groups > > Message-ID: > > <cama81sgslqteehsrrpko+uezxunrnf13l9230zb2vroy66z...@mail.gmail.com> > > Content-Type: text/plain; charset=ISO-8859-1 > > > > Does a ping of 1496 work, but not 1497? > > > > Remember in Q-in-Q the four-byte overhead, on our 3560s we need to set > the > > system MTU to 1504. Not sure if that is the same problem or not, but you > > should define exactly where the break in size first as part of your > > troubleshooting. > > > > Les > > > > > > On Sun, May 12, 2013 at 5:55 PM, Eric campbell <[email protected] > >wrote: > > > >> First I would apologize to the other poster for inadvertently Hijacking > >> his thread. > >> > >> > >> I will start a new thread at this point and maybe That will work. > >> > >> > >> Folks, > >> > >> I just want to start off by saying thanks to all of the regulars in the > >> group for the consistent knowledge sharing. > >> > >> I am a long time Lurker, but I have stumbled onto something which has > me > >> puzzled to say the least. > >> > >> I am attempting to create a bridge domain between two interfaces on an > >> ASR 1006 and am running into a strange MTU issue. > >> > >> > >> Everything is working fine I am tunneling my q-in-q/802.1q traffic > >> popping and pushing the necessary tags and what not, however when I try > >> to ping accross it using a 1500 byte packet with the df bit set i > >> cannot. I can ping across it with a 1400 byte packet but of course this > >> is not the magic number. > >> > >> I have tried setting the MTU at the > >> interfaces involved (gig interfaces) but cannot for the life of me > >> figure out why this is happening. This happens with a single tag as well > >> as a stack of them. I do not have a BDI interface at the moment, but I > >> am not sure i really need one since I am transiting the box. The only > >> thing that i am able to think of at the moment is some sort of system > >> wide MTU setting. This may become a no duh moment for me in the end, but > >> I cannot find the command if it exists. Any guidance would be > >> appreciated. If there is any information that is lacking let me know and > >> i will get it out here. > >> > >> > >> This is a rather small test environment at the moment. > >> > >> I have an Adtran 8044 - directly to the ASR on gig 0/1/1 the ASR then > >> bridges this traffic to the interface Gig 0/1/2 - which then places it > on > >> the wire as a single tagged trunk going into a 6509 trunk port and > finally > >> terminating on an SVI. On the other side of the Adtran is a simple > laptop > >> connected to the 8044 which is where I am originating the 1500 byte > pings > >> that terminate to the SVI on the 6509. > >> > >> The 8044 simply takes the packet in as a native packet in this case, > >> applies a 802.1q tag to it, and then ships it out a trunk port to the > ASR. > >> The 8044 has a MTu set at 2000 on this port, The ASR has an interface > level > >> MTU of 1600 and the 6509 has an MTU of 1500. Also I have tried it with > the > >> MTu set at Max on the 6509 as well. Like I said I am sure that in a > setup > >> as small as this the answer is staring me in the eye. > >> > >> Since the 6509 is receiving a trunk port off of the ASR with a single > tag > >> applied I feel the problem is probably not there. The Adtran takes the > >> taffic in from the laptop at 1500 MTU and then applies its tag then > >> shipping it out. > >> > >> I have also tried performing this ping from a 7206 I have that is spare > >> set up like the laptop in this case using the same parameters. > >> > >> Thanks for assisting > >> > >> > >> > >> Thanks to all, > >> Eric > >> _______________________________________________ > >> For more information regarding industry leading CCIE Lab training, > please > >> visit www.ipexpert.com > >> > >> Are you a CCNP or CCIE and looking for a job? Check out > >> www.PlatinumPlacement.com > >> > >> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >> > > > > > > > > -- > > Les Waller, Network Engineer ..:|:..:|:.. > > > > Home Page: *http://www.facebook.com/groups/325762454132531/* > > * > > *MBA, CISSP, CCNP/CCDA > > > > > > ------------------------------ > > > > Message: 2 > > Date: Mon, 13 May 2013 08:58:55 +0300 > > From: Imran Ali <[email protected]> > > To: "[email protected]" <[email protected]> > > Subject: [OSL | CCIE_RS] pim accept-rp > > Message-ID: > > <cah7egzdfkfyvfsrguc3-q5wszwyacjibepo7sjoyxestufu...@mail.gmail.com> > > Content-Type: text/plain; charset=ISO-8859-1 > > > > hi all > > > > guys if we are using auto rp , and let say task suggest we allow > only > > *,G joins only for active groups. > > > > do we need to allow auto rp groups in accept rp ? > > > > ip pim accept-rp auto ALLOWED > > > > ip access-list ALLOWED > > permit 224.0.1.40 > > permit 224.0.1.39 > > permit 224.1.1.1 > > > > > > ------------------------------ > > > > Message: 3 > > Date: Mon, 13 May 2013 12:13:21 +0400 > > From: Saleh Batouq <[email protected]> > > To: Imran Ali <[email protected]> > > Cc: "[email protected]" <[email protected]> > > Subject: Re: [OSL | CCIE_RS] pim accept-rp > > Message-ID: > > <caezok32zd7ou9nx2uc1qy9la-m6+mchof921l4fbap8j05k...@mail.gmail.com> > > Content-Type: text/plain; charset=ISO-8859-1 > > > > I understand from your question is that you need to only use the SHARED > > TREE (*,G) and not to build the SOURCE BASED TREE (S,G) so you have only > > two options. > > 1. ip pim spt-threshold infinity ACL . where the ACL is a standard acl > that > > specify the Groups. > > 2. biderectional pim. Enabled in your network. > > On May 13, 2013 10:04 AM, "Imran Ali" <[email protected]> wrote: > > > >> hi all > >> > >> guys if we are using auto rp , and let say task suggest we allow > >> only > >> *,G joins only for active groups. > >> > >> do we need to allow auto rp groups in accept rp ? > >> > >> ip pim accept-rp auto ALLOWED > >> > >> ip access-list ALLOWED > >> permit 224.0.1.40 > >> permit 224.0.1.39 > >> permit 224.1.1.1 > >> _______________________________________________ > >> For more information regarding industry leading CCIE Lab training, > please > >> visit www.ipexpert.com > >> > >> Are you a CCNP or CCIE and looking for a job? Check out > >> www.PlatinumPlacement.com > >> > >> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >> > > > > > > ------------------------------ > > > > Message: 4 > > Date: Mon, 13 May 2013 11:29:56 +0300 > > From: Houssam Chahine <[email protected]> > > To: "[email protected]" <[email protected]> > > Subject: [OSL | CCIE_RS] Proctor Labs > > Message-ID: > > <capapdxcqy1dqu_oijiufpj24cho0hezryktte7auiv4zj2y...@mail.gmail.com> > > Content-Type: text/plain; charset=ISO-8859-1 > > > > I have a small question dedicated to the Teachers, > > > > I am practicing recently using proctor labs, and my question is, is there > > any possibility once you load the initial configuration, it doesn't load > > perfectly? Today i was doing Vol3-Lab2C. Many tasks that i was supposed > to > > configure was already there, for example: > > > > 1- I was supposed to enable " Portfast Trunk" on the appropriate > interfaces > > but it was already there. > > 2- I am supposed to have a problem pinging BB1, but i didn't face any > > problem pinging it. > > 3- on Cat1 fa 0/11 i was supposed to disable port security for mac > > 0006.5331.9e41 which was not there... instead i had a log error since the > > moment i typed my credentials, "Security violation caused by MAc > > 0000.0000.0001 ... > > 4- There is still some that didn't come to my mind now. > > > > In brief, for the second time so far, once i compare the initial config > of > > some devices to the initial config file that comes with the book, i found > > there is difference, or the task that i am suppose to accomplish, is > > already preconfigured. > > > > Please advise. > > > > > > End of CCIE_RS Digest, Vol 88, Issue 8 > > ************************************** > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > Are you a CCNP or CCIE and looking for a job? Check out > www.PlatinumPlacement.com > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
