XPost: comp.os.linux.networking   
   From: grahn+nntp@snipabacken.se   
      
   ["Followup-To:" header set to comp.protocols.tcp-ip.]   
      
   On Wed, 2010-09-29, Mark Hobley wrote:   
   > On Wed, 29 Sep 2010 17:16:12 +0000, Mark Hobley wrote:   
   >   
   > I have some more weirdness now. If I ping from one host to another, connected   
   > via ethernet, I would expect a maximum datagram size of 1500. However, I   
   > actually get a result of 65535, as follows:   
   >   
   > # PMTUD is disabled on both hosts:   
   > echo 0 > /proc/sys/net/ipv4/ip_no_pmtu_disc   
   >   
   > ping -s 65507 miranda   
   > PING miranda.markhobley.yi.org (10.0.0.30) 65507(65535) bytes of data.   
   > 65515 bytes from miranda.markhobley.yi.org (10.0.0.30): icmp_seq=1 ttl=64   
   > time=13.8 ms   
   >   
   > Does this mean that jumbo frames have become enabled on my network?   
      
   No, it means you should install and use[1] tcpdump to see what this   
   actually translates to on the Ethernet level.  Hint: IP fragmentation.   
      
   /Jorgen   
      
   [1] If you have root access on either machine, that is.   
      
   --   
     // Jorgen Grahn    O  o   .   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)