Sunday, November 20, 2011

Connecting to Cytanet using own modem

UPDATE: The DSL Access and Netrunner merge is complete, and the modem I use no longer seems to work with the configuration below.

Cytanet, the ISP I'm using, gives out Thomson TG585v7 modems to their customers. However, the modem is in-famous for its lack of features and performance. The ISP's using it also have a tendency to lock it down, and I got the dreaded NAT Type 3 on my PS3, despite forwarding all ports to it. Cytanet also uses a weird configuration only for its simplicity, because every single user just wants Facebook right?
Some people have had problems that made them switch to another ISP, others, however, have perfect service and get the advertised speeds. I happen to be near one of their exchanges, so I get good performance, which was also improved when I changed modems, from a Thomson 585v7 to a TP-Link W8920GB.
The Thomson modem suffers from ISP lock-down and retarded configuration. It is also slow to sync and browsing the configuration pages makes you angry.
Cytanet currently configures the modem as a router as well, but since I am not a networking expert I used the old method, back when they gave out B-Focus modems with bridge only mode.

I have a TP-Link W8920G and a Linksys WRT160N with DD-WRT, connected to the 1st Ethernet port of the TP-Link. I used the TP-Link only as a modem, since all the configuration of port forwards, QoS, etc was done on the Linksys router.

1. Create a Bridging connection, with VPI/VCI 8/35, and LLC encapsulation
2. Create a virtual lan/bridge between the port the router is connected and the bridge
3. Set the router to clone the mac address of the Thomson modem
4. Set the router to use DHCP for its WAN connection


The modem should become a bridge-only device, with only one port being able to access the internet. The other 3 ports on my modem can be used to access its configuration.
The router should get a public IP address, since Cytanet identifies it as the old modem because of the fake MAC.

The TP-Link syncs almost immediately, unlike the Thomson which took about 10-15 seconds. The latency also dropped by around 80ms as well. The PS3 also shows "Nat Type: 2".


I will some day attempt to enable the modem's router mode, because I don't want to trash the remaining 3 ports and Wi-Fi, and also try to make devices that connect through them use the Linksys router's DHCP.

1 comment:

  1. Any news on how to configure a new modem after the DSL access with netrunner merge?

    ReplyDelete