MTU on Firewall low

[godonga]

Hi All

I have been experiencing some slow uploads to a certain website we do business with, at times the uploads will time out. The research I did pointed out to a low MTU some where along the path which causes fregmentation of packets. I got a utility from the Internet which traces the MTU's of the routers on the path. the first two routers within my network give me 1500 (which is the default) and I get 576 on the firewall and subsequently on every router there after. An ifconfig -a shows an MTU of 1500 on the interfaces. Is there a parameter in Checkpoint which sets the MTU or it uses the default one set in Solaris on the Interfaces. Any ideas of how to increase it are most welcome.

Regards
G