Forum Discussion

Cirrus

Oct 03, 2019

Test access sourcing from float

To test firewall rules we telnet to the pool member's service port, which proves access for the self IPs, but not for the float. Anyone know how to source from the float?

# telnet -b floating_self_ip destination_ip

-b hostalias
        Uses bind(2) on the local socket to bind it to an aliased address (see ifconfig(8) and the ``alias'' 
        specifier) or to the address of another interface than the one naturally chosen by connect(2).  This 
        can be useful when connecting to services which use IP addresses for authentication and 
        reconfiguration of the server is undesirable (or impossible).

Be aware of route domains; https://devcentral.f5.com/s/question/0D51T00006i7apM/telnet-to-server-from-f5.

Andrew-F5

Employee

Oct 14, 2019

# telnet -b floating_self_ip destination_ip

-b hostalias
        Uses bind(2) on the local socket to bind it to an aliased address (see ifconfig(8) and the ``alias'' 
        specifier) or to the address of another interface than the one naturally chosen by connect(2).  This 
        can be useful when connecting to services which use IP addresses for authentication and 
        reconfiguration of the server is undesirable (or impossible).

Be aware of route domains; https://devcentral.f5.com/s/question/0D51T00006i7apM/telnet-to-server-from-f5.

jwlarger
Cirrus
Oct 17, 2019
Thanks!
jwlarger
Cirrus
Oct 18, 2019
Tested today with no joy. v11.6.3, only one route-domain (0). Selecting the floating self IP results in:
Cannot assign requested address
No connection.
Escape character is '^]'.
SetSockOpt: Bad file descriptor
- Andrew-F5
  Employee
  Oct 18, 2019
  Do an 'ifconfig' at bash then look for the vlan name for that floating IP or look for the IP itself.
- Lidev
  MVP
  Oct 18, 2019
  same result on v13.1, I'm going to end up believing that there's no way to test flows from floating IP 😳 (nc -s give the same bind failed).
  Any others solutions ? @Andrew C. - F5 Support Engineer
  - Andrew-F5
    Employee
    Oct 18, 2019
    It appears that we associate the non-floating self-ip to the VLAN despite the floating *also* using the same vlan.
    
    The linux subsystem references TMM's VLANs as physical interfaces, non-floating IPs are assigned to the VLAN as you'll notice with "ifconfig".
jwlarger
Cirrus
Oct 18, 2019
Tried both in tmos and bash on the original ltm from the start. Just tried again with another ltm with only one vlan & float. Same error 'cannot assign'.