Packet Length greater than MTU Post: 302500819

Sponsored Content

Special Forums IP Networking Packet Length greater than MTU Post 302500819 by DGPickett on Tuesday 1st of March 2011 03:46:38 PM

03-01-2011

Registered User

Sometimes localhost, a software device, has a big MTU, like 8K, and it may apply for all local packets. Ethernet is 1500 total, and the payload is less IPV4 40 bytes plus 4 x any options. It seems like the app should be allowing frag if using non-tcp, and tcp is a stream, so the app has no business fussing with packet bits and lengths.

It may be PATH MTU testing, where the routing tables is extended with dynamic host route lines and the MTU of path to host. If ICMP says the packet does not fit, it will retry with a lower size, hence it does not want fragmentation, it wants PATH MTU information. Black holes are when firewalls block that ICMP informations, and the PATH MTU has to time out and assume it went into a black hole, and try a lower packet size to ensure a route exists.

Not Solaris, but you should see similar:

Code:

$ netstat -rn
Routing tables
Dest/Netmask          Gateway            Flags  Refs       Use  Interface  Pmtu
127.0.0.1             127.0.0.1          UH       0   64980021  lo0        4136
191.136.182.236       191.136.182.236    UH       0   23515341  lan7       4136
191.136.182.0         191.136.182.236    U        2          0  lan7       1500
127.0.0.0             127.0.0.1          U        0          0  lo0        4136
default               191.136.182.1      UG       0          0  lan7       1500
$

DGPickett

View Public Profile for DGPickett

Find all posts by DGPickett

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

How to change the MTU in Unix registry?

Does anyone know how to or know of a web page where I can find how to change the MTU speed in Unix registry? Any info. would be greatly appreciated. Thanks, Techie

2. UNIX for Dummies Questions & Answers

length of data greater than 11

I need to get all the rows in a file, for which length of field at column 6 is greater than 11. I tried awk '{ if ($#1 >11) print $1}' filename But Iam getting some errors I tried different combinations like awk '{ if (${#$1} >11) print $1}' filename awk '{ if (${#1} >11) print...

3. Solaris

MTU Value

Hi guys, Do anyone know how to change the MTU value on an interface on Solaris 10 server?

4. Solaris

how to find MTU size on solaris.

How do i find the MTU size on solaris, which file to look into. Please help I'm a newbie to administration.

5. IP Networking

Importance of LS length in DB exchange start packet (OSPF protocol)?

Is there any importance of LS length in DB exchange packet of OSPF protocol as its should be always be 20 bytes. Is this length to be ignored

6. HP-UX

MTU size

Hi, Just want to ask on how to check and change the MTU size of the nodes from 1500 to 9000? I need to match the MTU size of some cluster nodes which has 1500 to the others with 9000 because they are inconsistent. Thanks

7. Shell Programming and Scripting

Delete words greater than a specific length

HI All, I have a file with contents like this: apple computer terminal applecomputernetworkrouterterminalrouter network router applecomputernetworkrouterterminalrouter I want to remove all lines with length greater than "18 alphabets". Hence, my output should be: apple computer...

8. UNIX for Dummies Questions & Answers

MTU setting for IRIX

Couldn't find an IRIX forum, so I'm posting to this one... Just had our SAs rebuild an IRIX machine and now I need to set the MTU to 1344 (vice 1500 default). I can set it manually using the ifconfig command, but it won't survive a reboot. I made an entry into the /etc/init.d/ifconfig-1.options...

9. AIX

Packet loss coming with big packet size ping

10. Solaris

Set MTU value for ipv6 interfaces

Hi, I am trying to set mtu value for ipv6 interfaces. I know how to set it for ipv4 interfaces ifconfig net1 mtu 1240 Do I need to add any iptype for the above command ? Note: OS:Solaris 10 TIA

LEARN ABOUT REDHAT

slist

SLIST(1)							       slist								  SLIST(1)

NAME

       slist - Lists available NetWare Servers

SYNOPSIS

       slist [ pattern ]

DESCRIPTION

       slist lists all NetWare Servers available in your network.

       If slist does not print to a tty, the decorative header line is not printed, so that you can count the servers on your network by doing

       slist | wc -l

OPTIONS

       pattern
	  pattern is used to list only servers whose names match the specified pattern. For a server to be listed, the pattern must match the full
	  server name. You can use wildcards for the pattern, but you must protect these wildcards from any command  line  expansion  by  quoting.
	  Case doesn't matter.

EXAMPLE

       slist "I*"

       or

       slist "i*"
	      List all available Netware servers on your Network, that begin with an "I".

SEE ALSO

       ncpmount(8), ncpumount(8), pqlist(1), nprint(1)

CREDITS

       slist was written by Volker Lendecke (lendecke@math.uni-goettingen.de)

BUGS

       slist works only in IPX environment, as it uses SAP to find first server and then Bindery to get list of servers.

slist								    01/07/1996								  SLIST(1)

10 More Discussions You Might Find Interesting

1. UNIX for Advanced & Expert Users

How to change the MTU in Unix registry?

Discussion started by: Techie_girl

2. UNIX for Dummies Questions & Answers

length of data greater than 11

Discussion started by: thanuman

3. Solaris

MTU Value

Discussion started by: shabu

4. Solaris

how to find MTU size on solaris.

Discussion started by: ramky79