SIP phone issues with Belkin ADSL Wireless Router

The old Linksys WAG54Gv2 died so I replaced it with a brand new Belkin F5D7633uk4A. Everything working fine except two SIP accounts on my Siemens Gigaset S450 IP (“Authentication error”). Also I got authentication errors and SIP 408 Timeout with X-Lite using the same SIP accounts.

Also, Belkin web interface can not manage static routes, which is bad.

Version info:

Runtime Code version F5D7633-4Av1_UK_1.00.17
Boot Code Version 1.0.37-5.15
Hardware Version V1.0J3
ADSL Modem Code Version A2pB018e.d16f

Looks like there’s a transparent SIP proxy running on the router. I could ssh with admin username and web interface password to the router. Finally found siproxd running!

How to disable siproxd:

siproxd disable
save
reboot

How to add a static route:

route add IP NETMASK GATEWAY
save

All available commands:

?
help
logout
reboot
adsl
atm
brctl
cat
ledctrl
df
dumpcfg
echo
ifconfig
kill
arp
defaultgateway
dhcpserver
dns
lan
passwd
ppp
remoteaccess
restoredefault
route
save
swversion
wan
ping
ps
pwd
siproxd
sntp
sysinfo
tftp
wlctl