Issue w/ Mikrotik Routerboard 750

[Bobacus]

So I picked up a Routerboard 750 to try out since it was pretty much dirt cheap ($40) and ipv6 compatible.

Although after punching in the basic settings, I've come across quite a strange issue. First of all it does not seem to like my Cisco 2900 XL switch, when I have it plugged into the lan it won't pass packets at all. No biggie, upgrading to a gigabit switch later, and I only have a few items plugged in anyways.

The weird issue is when I try to set a static IP on the wan port. Right now I have the router plugged directly into my cable modem (Motorola SB5101 on Cox Communications.) It works great when I let it run with the DHCP address assigned by Cox, although when I try to set the static IP address that i've been assigned by cox, I see about 50% packet loss, if not more. I know it isn't the address, since I've been using this address for quite some time on other devices with no issues.

Any help I can get on this will be great, I tried the MikroTik forums, although an admin has to approve your first message, which hasn't happened even though I tried to post over 24 hours.

 

[AMD_Gamer]

Why do you need to set it as static? are you sure you are configuring everything like DNS?

the 2900XL problem might be because you are not using a crossover cable and the newer switches you used to solve the problem are using auto mdix.

 

[Bobacus]

Good point on the crossover cable, doh. The whole Auto-mdix bit always bites me in the butt.

I have the dns set in the device, anyways I'm pinging by ip address so that shouldn't matter. I'm using a static for the ftp/mail/web that I host for myself here at the house.

To me it is just weird that dhcp works just fine, while a static address has a 50% packet loss. It almost makes me think there might be a compatibility issue, although what is strange is that before I was trying to split my internet between the mikrotik and a pix, and when I ran it through a vlan on my 2900 it showed the same issues that disappeared when plugging straight into the modem. A little annoying that the issue came back after I moved stuff around.

 

[Bobacus]

Well I fiddled with a few things, and it turns out the MikroTik has been dropping the arp entry for the gateway at Cox, it's a Cisco device of some sorts on Cox's end.

I seem to have fixed it by adding a static entry to the arp table for Cox's router, now why this works, it's not a permanent solution, since I don't want a surprise when Cox changes out that device.