How does one add 192.168.100.x as a secondary alias IP?

[Almighty1]

Just recently got a Arris SurfBoard SB8200 DOCSIS 3.1 Cable Modem to replace the SB6190 and it seems the SB8200 Cable Modem is picky about which 192.168.x.x blocks it will allow to connect to the status page at 192.168.100.1 port 80 even though both ping and traceroute works but it will just time out, connecting directly via ethernet from the computer works fine while no devices like mobile devices, desktop/notebook computers would work. So the remedy is to set the LAN IP on the ASUS RT-AC68R to 192.168.1.1 from 192.168.2.1 as in my case and then access the webpage at 192.168.100.1 and then switch the LAN IP on the ASUS RT-AC68R back to 192.168.2.1 and the status page will work fine until the Cable Modem is rebooted or power cycled, then the remedy will need to be used again. 192.168.10.1 as the LAN IP will work fine without needing to do anything. Now my question is, is it possible to add a alias IP to the ASUS RT-AC68R using RMerlin so that it too has a 192.168.100.x IP when communicating with the modem. If so, how does one do this? Thanks in advance!

 

[ColinTaylor]

https://www.snbforums.com/threads/access-modem-configuration-page.11957/page-2#post-289752

 

[Almighty1]

Thanks, looking at post #33 in that thread, I can see how the scripts in post #34 would work but if the WAN interface was configured with a static IP of 192.168.100.2, will the router still pull the dynamic IP for the WAN interface via DHCP since I thought for the DHCP to work, one had to set the WAN to DHCP. Seems like this won't be a solution if I got the GT-AC5300 as that is not supported by Merlin.

 

[ColinTaylor]

I think you need to ignore post #33. Just use your normal WAN setup with eth0 getting its settings from DHCP, then when the WAN interface comes up it will create another interface at eth0:0

 

[Almighty1]

Actually, it seems like they are making it more complicated than it needs to be since the thing is, it is supposed to be done using ifconfig as that is how I do it on FreeBSD which is using the reference standard TCP/IP stack...

So if it was eth0 for example, then it would be:

ifconfig eth0:0 192.168.100.88 netmask 255.255.255.0 up

You can basically add as many secondary addresses as you want as you just name it eth0:1, eth0:2, etc where the number after the : is the secondary IPs.

admin@188:/tmp/home/root# ifconfig br0:0 192.168.100.88 netmask 255.255.255.0 up
admin@188:/tmp/home/root# ifconfig
br0       Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet addr:192.168.2.1  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::b27f:b9ff:fe83:622f/64 Scope:Link
          inet6 addr: 2601:645:c201:2ab::1/64 Scope:Global
          UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
          RX packets:3232761 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1325536 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:405259252 (386.4 MiB)  TX bytes:236681746 (225.7 MiB)

br0:0     Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet addr:192.168.100.88  Bcast:192.168.100.255  Mask:255.255.255.0
          UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1

eth0      Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet6 addr: fe80::b27f:b9ff:fe83:622f/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5346759 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5482784 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3655397239 (3.4 GiB)  TX bytes:1598855647 (1.4 GiB)
          Interrupt:181 Base address:0x6000

eth1      Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet6 addr: fe80::b27f:b9ff:fe83:622f/64 Scope:Link
          UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
          RX packets:1291808 errors:67 dropped:0 overruns:0 frame:3833111
          TX packets:1598172 errors:3642 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:824580800 (786.3 MiB)  TX bytes:334173014 (318.6 MiB)
          Interrupt:163

eth2      Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet6 addr: fe80::222:15ff:fea5:304/64 Scope:Link
          UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
          RX packets:5822822 errors:0 dropped:0 overruns:0 frame:1270633
          TX packets:7777543 errors:14613 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1033724210 (985.8 MiB)  TX bytes:4122113396 (3.8 GiB)
          Interrupt:169

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING MULTICAST  MTU:16436  Metric:1
          RX packets:2780355 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2780355 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:723259045 (689.7 MiB)  TX bytes:723259045 (689.7 MiB)

vlan1     Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet6 addr: fe80::b27f:b9ff:fe83:622f/64 Scope:Link
          UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
          RX packets:8037 errors:0 dropped:0 overruns:0 frame:0
          TX packets:308887 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:943126 (921.0 KiB)  TX bytes:42221558 (40.2 MiB)

vlan2     Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet addr:73.15.214.181  Bcast:73.15.215.255  Mask:255.255.254.0
          inet6 addr: 2001:558:6045:44:c9f6:c051:78ce:df03/128 Scope:Global
          inet6 addr: fe80::b27f:b9ff:fe83:622f/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:5467964 errors:0 dropped:0 overruns:0 frame:0
          TX packets:5173989 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:3634001837 (3.3 GiB)  TX bytes:1542274061 (1.4 GiB)

 

[ColinTaylor]

So if it was eth0 for example, then it would be:

ifconfig eth0:0 192.168.100.88 netmask 255.255.255.0 up

But that's exactly what they're doing, so I'm not seeing your point. The only difference is they're using 'nvram get wan0_ifname' instead of eth0 so that it's compatible with all router models.

 

[Almighty1]

What I was saying is scripts and stuff is only possible with Merlin or third party firmware but not ASUS's own. In my case, since I am using Merlin, it didn't work when I did it on br0:0 as even ping failed. vlan2 is the one with the WAN IP address so I took the br0:0 down and then did it on vlan2:0 which pings except from the LAN side, I can't reach 192.168.100.1 at all but it works when br0:0 is taken down so there is something else missing. Tried eth0:0 and it doesn't ping either. I am just looking for a method that will work as I am planning to get the GT-AC5300 which is not supported by Merlin so I have to use the ASUS OEM firmware instead and it seems like I might have to do the iptable command to get it to work except not sure how to do it manually.

 

[ColinTaylor]

My best guess (and it is a guess) is;

1) reboot router to clear out any existing customisations

2) enter the following

iptables -t nat -I POSTROUTING -o `nvram get wan0_ifname` -j MASQUERADE
ifconfig `nvram get wan0_ifname`:0 192.168.100.2 netmask 255.255.255.0

3) test

 

[Almighty1]

Actually, the problem is not the command(s) since the command(s) is doing the routing correctly
but it is basically the original problem. When the LAN IP is set as 192.168.2.x or 192.168.0.x subnets, it will timeout trying to open port 80 (status page) on 192.168.100.1 but port 8080 (spectrum analyzer) will work fine. However, if I change the LAN IP to any other subnet in 192.168.x.x and then open port 80, it will work and all I have to do is change the LAN IP back to 192.168.2.x and port 80 will continue working. Others have this problem too if a router of any make is involved but works fine if it's direct from the computer by ethernet cable.

 

[ColinTaylor]

OK. Then I'm out of ideas. The solution above is used by other to access cable modems on 192.168.100.1 but there's obviously something different about your modem. I can't imagine why changing the LAN IP would have any bearing unless the cable modem uses 192.168.0.x and 192.168.2.x itself (in which case there could be a conflict).

Personally I would just use 192.168.1.x as my LAN and avoid the problem altogether.

 

[Almighty1]

Usually, that solution is supposed to work as the SB6183 which was also broadcom chipset based has that problem but probably a different problem with the SB8200 which is also Broadcom based. The SB6190 which is Intel Puma 6 based works fine without having to use any solution at the same 192.168.100.1 address. Arris can't duplicate the problem but others had the problem and they were using ASUS and D-Link routers but the person using a pfsense box with the Ubiquiti access point didn't have the issue with the same 192.168.0.x address. It was the others who found that using 192.168.1.x that worked, I was the one who found out that I can change the IP address back to the problem IP after accessing the status page and it will continue to work on dslreports.com.

The fix isn't a big issue as long as I don't have to reboot the cable modem since I just have to do the fix once. I'm using 192.168.0.x for the local LAN for things that go through the Cisco wired managed 10GB switch and 192.168.1.x is used by the DSL Modem so thought 192.168.2.x was safe except there are some devices that have the IP configured on the IP side so when I changed routers, I will probably slowly migrate them.

 

[jegesq]

Like Colin wrote, why don't you just set your LAN address to 192.168.1.x, a range from which you say you have no difficulty accessing the modem's GUI at 192.168.100.1? Even if you want to create a separate subnet, do you really need to be able to access the modem's GUI from every device on your network?.

Just not seeing the utility of what you're trying to accomplish. What am I missing here?

 

[Almighty1]

It's easier said than done to set the IPs on the network to 192.168.1.x since I rather use another subnet for everything that goes through the consumer cable internet and router. The DSL Modem/Router handles the entire 192.168.1.x and is wired and goes through my FreeBSD server as the actual router as that is served by a block of static IPs from a provider. I'm keeping things on separate subnets for a reason. Also, many devices on my LAN have the IP set on the device itself like my HP OfficeJet Pro x576dw and my home alarm system which runs on a Wireless ethernet bridge which means if it starts complaining of trouble because of a communications failure, it will beep 3 times every 30 seconds for 10-12 hours. Right now, I don't have the time to reconfigure the entire LAN. And yes, I do really need to access the modem's GUI from different computers on the network since it is not device dependent as it depends on the router since if one device cannot access it, none of it can and if one device accesses it with the fix, then all the devices can do it. I mean I am not going to be rebooting the cable modem that often and only now because there seems to be packet loss as I'm getting frequent no surf while waiting and timing out even for replying here, I have to hit post reply a second time after 30 seconds as it will just sit there on waiting, need to solve that problem first. Besides, it's a lot easier to reboot the router with the fix than having to reconfigure the entire LAN just to fix a minor problem. If I had that much time, I would have already put in the GT-AC5300 router that is sitting here.

 

[Almighty1]

Looks like the problem is the modem as Arris Engineering and their labs had confirmed here:
https://www.dslreports.com/forum/r31446178-SB8200-Webpage-problems

 

[Fitz Mutch]

Maybe try this? My router is RT-AC68U and this is what I had to do.

/usr/sbin/iptables -t nat -I PREROUTING -i br0 -d 192.168.100.1 -j RETURN
/usr/sbin/iptables -I FORWARD -i br0 -d 192.168.100.1 -j ACCEPT

 

[Almighty1]

The issue seems to be a problem only with routers on the Broadcom chipset as Marvell and Qualcomm/Atheros seems to work fine.

 

[Manny]

HI,

unplug the SB8200 then plug it back in. ComCast pushed out a fix Today

 

[Almighty1]

HI,

unplug the SB8200 then plug it back in. ComCast pushed out a fix Today

The fix is only to change the diplexer from 1.2Ghz to 1.0Ghz to reverse the workaround which was needed for the Cisco CMTS except it was causing T3 resets for those on the Arris E6000 CMTS while the original problem for Cisco CMTS already had a fix so the current fix is nothing more than a configuration file and not a software update as netdog who is the Arris Engineer and the lab was able to duplicate the issue with certain subnets not working and are still working on a fix for it.

 

[Manny]

The fix is only to change the diplexer from 1.2Ghz to 1.0Ghz to reverse the workaround which was needed for the Cisco CMTS except it was causing T3 resets for those on the Arris E6000 CMTS while the original problem for Cisco CMTS already had a fix so the current fix is nothing more than a configuration file and not a software update as netdog who is the Arris Engineer and the lab was able to duplicate the issue with certain subnets not working and are still working on a fix for it.

I receive the same T3 event on my Arris BS6190 I am replacing the BS6190 with the Arris SB8200 this weekend, I will run some tests. Netdog is all over it.

My last T3 event was on the 25th

 

[Almighty1]

I receive the same T3 event on my Arris BS6190 I am replacing the BS6190 with the Arris SB8200 this weekend, I will run some tests. Netdog is all over it.

My last T3 event was on the 25th

I noticed on my SB8200, the log no longer has more than 5 entries as the first 4 is the January 1, 1970 event which is from the reset to factory defaults reboot on the 26th and then the 5th entry is the T3 timeout except that one just keeps getting replaced with the newest one. Yesterday it said 27th and today it said the 28th, this is what others reported as well.