Category:Juniper -> Routing and Switching
1. Enable TCP MSS adjust. The MSS adjustment is there to influence the client and server ends to drop the TCP segment size.
2. Configure IP MTU. The ip mtu is there to force the router to send an ICMP message back to the sender if the packet is too large (standard 1500 bytes) (Path MTU Discovery). By default, path MTU discovery on outgoing TCP connections is enabled on Juniper SRXes (https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/pmtu-discovery-configure.html). Make sure Jumbo frames are enabled on all transit FWs, else allow ICMP messages which are used by PMTU discovery.
3. Set DF-bit value to 0 for all UDP datagrams which match the length between 1400 and 1500 bytes.
