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SRP 527W - can use for routing subnet other than NAT?


I'm wanting to use the SRP527W (from Telstra) to route a block of assigned internet addresses (/29) over the WAN internet IP address. Is this possible on the 527W, or does it only do NAT routing?

thanks in advance,

regards Aaron

Andrew Hickman
Cisco Employee

Hi Aaron,

Does this /29 include the WAN IP address, or is it routed via a separate WAN IP?

If you have one of the original SRP527s running 1.1.x code, then your options here are limited - if the /29 is a separate block, you could turn off NAT and route the subnet.  That probably doesn't provide the solution you require though.

If you have a newer SRP527W-U device running 1.2.x code, then there are more options.  If the /29 includes the WAN IP, then you can use port forwarding or the hardware DMZ features.

If the subnet is routed, then you can use the NAT bypass feature that was recently added in release 1.2.4.

Hope that helps,



thanks for the reply, the WAN IP is not in the /29 subnet. So routing it is my only way forward. Didn't know if it would do none NAT routing.

Device is new (being delivered to site in Darwin, I go there on Wednesday) so hopefully will be latest code so can turn off Natting and just route it. Idea of no IOS is a bit concerning, but if the features and capabilities are there should be ok.

NAT routing should be ok if you have an SRP527W-U-K9-G4.



ok got a SRP527W-U model, upgraded to 1.2.4(003), the WAN int is, turned off NAT, put in my Telstra assigned block as the LAN scope (, configured DHCP etc. I get assigned an address from the Telstra Internet assigned block, can ping the internet, speednet detected it etc, but when I try and ping back from the internet into the lan space it doesn't work. Have disabled the firewall etc. Any other ideas???


Hi Aaron,

I just tried this in my lab with an SRP521 and it seems to work ok.  I used a slightly different configuration though.

Instead of disabling NAT, I just added a NAT bypass rule for VLAN 1, which I readdressed to use the routed subnet.  No need to disable the firewall, traffic should just route directly.

When adding the bypass rule, just select the VLAN interface and leave the other settings as default ( for the addresses).

Try that and let me know how you get on - I appreciate you are using DSL instead of Ethernet in your case.



I have done the same way. Enabled the NAT and created a bypass rule for my LAN Pool. It is working fine.