Linux router i RPC

Please, help! Est set: NT server <-> HP-UX router (ne tolko router) <-> Cisco <-> vydelenka <-> Cisco <-> Linux router (tolko router) <-> NT server. Posle dobavleniya v etu cepochku Linux routera, Nt servera ne mogut ustanovit RPC connection, tochnee eto microsoft RPC - rabotaet po portu 135. Prichem, ne to chtoby sovsem ne mogut, posle restarta Linuxa minut 15 connection est, a potom glokhnet. Na Linux port 135 zakryt, no dla routinga on i ne nuzhen, ved sam Linux na etom portu ne slushaet, ili ya ne prav? Podskazhite khotya by gde iskat prichinu.