Hello all,
I’ve been using GNS3 for a while now and all is great.
Today, I’ve drawn a new network using the 6.40.1 version of CHR and I encountered an odd issue. I connected ether1 (with as valid dhcp-client setup) to a gns cloud and I wouldn’t an IP address. After a bit a troubleshooting, I noticed that ETHER8 was seeing a lot of traffic. Hmmm. I sent my dhcp-client to ether8 and voilà! I got my IP address assigned to me.
I relaunch GNS3, and it’s ether9 that is now seeing traffic.
OK, so I removed the router and added a new one using 6.39.2. OK! Now ether1 gets the IP address every time (Yes, I changed the dhcp client’s interface, of course). Restart GNS3 and it’s still ether1.
Has anybody else encountered this issue? I’d like some feedback from you guys before I write to support.
BTW, my config is blank besides the router’s name and the dhcp client. My version of GNS3 is 2.0.3. I love it since I don’t have to fool around with virtual interfaces and loopbacks in Windows anymore!! 
Regards,
EDIT: The host machine is running Windows 10 pro. Xeon E3-1270 with 16GB ram.
Update:
Mikrotik says it’s gns3 related. I’m not totaly convinced since this behavior started with ROS 6.40 and +
I also noticed that the firewall filters don’t work as expected. For example, I have two routers in the same broadcast domain. One is an L2TP client to the other. On the server, I added filters to DROP NEW and INVALID connections. The tunnel still came up. I tested that on real routers and the server blocked the L2TP client’s requests as expected (I’m doing this to illustrate to students the importance of knowing about your protocols and permitting them when required). This is present in the ROS 6.39.X versions. I haven’t tested all firewall actions, so I can’t say if it’s generalized behavior or not.
I’ll post more comments as I get information.
Hey, thats some good information so far.
Today I have been using CHR 6.42.6 in GNS3. I am also seeing odd DHCP behavior, sometimes it works as expected, others it doesn’t. Ill test on all interfaces and see what happens.
