SRX Services Gateway
Highlighted
SRX Services Gateway

TCP DUP messages

‎09-28-2016 07:13 AM

Some customers where i implemented SRX 300 and SRX320 models of the SRX i have strange problems with some websites. Not all of them. Just some.

 

When i wireshark the connection i see a lot of tcp-dup messages

 

Finally after adding the following line to the configuration the problem was solved

 

set security flow tcp-mss all-tcp mss 1400

 

Can anyone explain me what thit command exactly does ?

I already had an MTU of 1492 set on the wan connection

 

Regards,

 

Robbert

 

2 REPLIES 2
Highlighted
SRX Services Gateway

Re: TCP DUP messages

‎09-28-2016 09:10 AM

This sets the maximum segment size to 1400 bytes.  MSS is different than MTU.  MSS instructs the server and/or client to only send a maximum data packet size of 1400 bytes.  This only affects TCP.

Highlighted
SRX Services Gateway

Re: TCP DUP messages

‎09-28-2016 07:27 PM

Hi,

 

More details about this command are availabel at the following link :-

http://www.juniper.net/techpubs/en_US/junos12.1x46/topics/example/session-tcp-maximum-segment-size-f...

 

Regards,

Sahil Sharma

---------------------------------------------------

Please mark my solution as accepted if it helped, Kudos are appreciated as well.

Feedback