hey devestation a couple things , under the assumption you are running windows. and you mention that the server, "the srcds" and the client, "the steam launch of the game" are located on he same computer. to find the networkpaths of the host computer , in windows hit start then run and type "cmd" into the command line.
this will open the dosx interface at the cursor type " ipconfig/all ". this will list all of the network paths. example--------
F:\Documents and Settings\me>ipconfig/all
Windows IP Configuration
Host Name . . . . . . . . . . . . : imapc
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : cfl.rr.com
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : cfl.rr.com
Description . . . . . . . . . . . : NVIDIA nForce Networking Controller
Physical Address. . . . . . . . . : 00-xx-xx-xx-4E-BA
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 97.xxx.xx.95
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 97.xxx.xx.1
DHCP Server . . . . . . . . . . . : 10.xxx.xxx.1
DNS Servers . . . . . . . . . . . : 65.xx.x.111
65.xx.x.112
Lease Obtained. . . . . . . . . . : Friday, November 28, 2008 7:43:33 PM
Lease Expires . . . . . . . . . . : Saturday, November 29, 2008 4:02:07 AM
there are also two utilities which are very helpful with viewing whats going on on the network interface in real time. from the windows "sysinternals suite" is "TCPVIEW"
http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx after you install this you'll have to enable it as an exception in your firewall program. it allows you to see all of the tcp/udp ports that are open and each of the processes or applications which own that port. this was useful for me because i,m running winxp pro. the os had numerous ports open that,"I did not use or were orphaned". this allowed me to increase my network speed. finally there is
"ICB2000",http://tucows.ctcinternet.cl/preview/194739.html
this allows you to see your upstream and downstream rates in real time. very useful for maximizing your servers bandwidth cvars the sv/cl cmd and update rates. to match wat your network has available.