I would think the BOINC developers would also want a smarter program. Trying to connect when the network access is not present, and then refusing to connect when the network is present...

You can set the Network Activity to Suspended before you remove the network cable and put it back on "based on preferences" or Always available when you connect it again. Then you will only have the back-off when the project does not have internet access (e.g. when their servers are down).

BOINC cannot determine between the computer having no physical internet connection, the network cable being removed, the network card being broken, your ISP being down, the project servers not being up etc. etc. as they all have the same symptoms: There's no answer from over there.

Now, this can also be because the project servers are under too much stress, a deluge of computers trying to reach them, in a sense doing a directional denial of service attack. That's where the back-off comes in. For the "just in case there is a connection, but we're part of the DDoS attack, let's stop trying" cases.

When in back-off, you can do an Update on the project. When that doesn't work, go Advanced->Do network communication. Either of these will shake the back-off loose. And after you had all communications, suspend your network activity.

I'm not sure I understand you're situation. It sounds like you have several computers but only 1 network cable so you move the cable from 1 computer to another to give each one some connection time. Is that right?

I think you need to use the combination of the Network usage allowed override in combination with the "report results immediately" option that can be set through cc_config.xml (per computer).

By using the RRI option BOINC won't wait 24 hours trying to report the tasks.
By using the Network allowed override option (In the Advanced Preferences) you tell it when this happens.

Of course, if the computers have a constant internet connection, you don't need to use the Network allowed override. Then only the RRI option in cc_config.xml suffices.

<global_preferences>
<mod_time>1224055149.000000</mod_time>
<run_on_batteries />
<run_if_user_active />
<suspend_if_no_recent_input>0.000000</suspend_if_no_recent_input>
<start_hour>0.000000</start_hour>
<end_hour>0.000000</end_hour>
<net_start_hour>0.000000</net_start_hour>
<net_end_hour>0.000000</net_end_hour>
<work_buf_min_days>0.500000</work_buf_min_days>
<work_buf_additional_days>2.000000</work_buf_additional_days>
<max_ncpus_pct>100.000000</max_ncpus_pct>
<cpu_scheduling_period_minutes>60.000000</cpu_scheduling_period_minutes>
<disk_interval>60.000000</disk_interval>
<disk_max_used_gb>100.000000</disk_max_used_gb>
<disk_max_used_pct>50.000000</disk_max_used_pct>
<disk_min_free_gb>0.001000</disk_min_free_gb>
<vm_max_used_pct>75.000000</vm_max_used_pct>
<ram_max_used_busy_pct>50.000000</ram_max_used_busy_pct>
<ram_max_used_idle_pct>90.000000</ram_max_used_idle_pct>
<idle_time_to_run>3.000000</idle_time_to_run>
<max_bytes_sec_up>0.000000</max_bytes_sec_up>
<max_bytes_sec_down>0.000000</max_bytes_sec_down>
<cpu_usage_limit>100.000000</cpu_usage_limit>
</global_preferences>