Beefy Boxes and Bandwidth Generously Provided by pair Networks
good chemistry is complicated,
and a little bit messy -LW
 
PerlMonks  

Re: Check network MTU size

by gsiems (Deacon)
on May 23, 2013 at 22:07 UTC ( #1035031=note: print w/replies, xml ) Need Help??


in reply to Check network MTU size

++ We recently had this happen to us and it took a while to figure out what was going on. I shall have to try this.

Replies are listed 'Best First'.
Re^2: Check network MTU size
by 5mi11er (Deacon) on Jun 04, 2013 at 13:46 UTC
    I've had to rethink the "check for MTU larger than it should be" section. Checking for a larger MTU size is not as simple as this, because it will only work if the network segment (vlan) connected to the computer running the check is the one with the MTU set too large.

    As an example imagine the semi-simple case of a network like this

    -------A--------B--------C-------
      (1)     (2)       (3)     (4)
    
    Each of the four numbered, dashed areas is a network segment (vlan), the letters being routers.

    If our computer is located on segment 1, and sends out a ping larger than the actual MTU size allowed for segment 1, router A will drop that packet and not forward it on. So, if segment 2 or 3 or 4 is set to have an MTU size larger than segment 1, we would not be able to tell that from segment 1.

    To actually find out if the MTU size of any of the segments were larger than 1500, we would have to perform the large MTU ping test from each of the routers A, B and C.

    The testing for an MTU size being smaller in one network than the rest, is still valid, but it is unable to tell you which segment was at fault.

    -Scott

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1035031]
help
Chatterbox?
[LanX]: And the reason is: The world’s best players aren’t at this year’s Games after the NHL stopped its athletes from leaving in the middle of the season. ... LOL
[LanX]: horoba: you like ice hockey?
[choroba]: Like is a too strong word. But you can't evade it here.
LanX (for people wondering: yes field hockey still exists and is even more popular than Hasslhoff in Germany)
[Corion]: LanX: Ah, that explains a lot :)
[marto]: Nobody we spoke to in Berlin had a clue who Hasslhoff was
[erix]: heh: The Dutch do one thing very, very well
[LanX]: the sidekick of this blonde playboy model which was saving lives with her red bathing suit ... (what was her name again ...)
[choroba]: Pamela Anderson?
[choroba]: erix: I'm proud to be from a nation that also does one thing well

How do I use this? | Other CB clients
Other Users?
Others taking refuge in the Monastery: (14)
As of 2018-02-23 16:30 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    When it is dark outside I am happiest to see ...














    Results (303 votes). Check out past polls.

    Notices?