[Serusers] 477 response when registered with TCP

[mahesh]

Hi all,

I am using the following network configuration.

HOST1---NAT---Internet---HOST2

HOST1 and HOST2 are windows XP machines with SJPhone softwares. The NAT box 
has SIP ALG(Application Level Gateway), which modifies the SIP packets to 
replace the Private IP address with the Public IP address.

I am registering with iptel.org proxy server using TCP from both the 
machines. I am able to make a call from HOST1 to HOST2. But when i try to 
make a call from HOST2 to HOST1, i get an error which says, "477 
Unfortunately error on sending to next hop occurred(477/TM)". When I 
register using UDP, then i do not see this problem. Could someone tell me 
what I am missing here.

Thanks
Mahesh