You can resolve this issue by either increasing the range of source ports the appliance uses, or by disabling the automatic randomization used to assign source ports to outbound traffic.
Configure the Source Port Range
tcp-ip inet-lowport <value between 1,024 and 49,152>
SG300#(config)tcp-ip inet-lowport 16384
This will increase the range of available source ports from the default of 16K to the difference between 65,535 (max ports available) and this lowport specification. So, if you use 16,384 as the lowport value, then there are 48K ports in the new range.
Disable Source Port Randomization
tcp-ip tcp-randomize-port <enable|disable>
SG300#(config)tcp-ip tcp-randomize-port disable
Disables the new randomization algorithm and reverts to the old 4.x behavior
These commands are available in the following SGOS versions:
- 126.96.36.199 and later
- 188.8.131.52 and later
- 6.x all versions