Technical Information

This section describes the following technical information about the proxy cache software.

• "System Administrator and Proxy Webmaster Aliases"

• "Proxy Cache Connect Timeout and Parent Failover"

• "Rules for Pattern Matching for TTL Selection Property"

System Administrator and Proxy Webmaster Aliases

Netra j proxy cache software enables you to establish email recipients for mail that is addressed to root@netra_host_name or Postmaster@netra_host_name. When entering email addresses, make sure you specify addresses in a form compatible with your sendmail configuration. For example, if your mail system expects an address of a form login@nis_domain_name, mail sent to login@host_name is undeliverable.

Proxy Cache Connect Timeout and Parent Failover

The Netra j proxy cache server supports parent failover, in which, if the server's parent fails, the server switches to the next parent on its list. (See "To View or Modify Proxy Cascade Properties" for a description of the table of parent proxies.) Failover occurs if the Netra j proxy cache server's TCP connect call fails, not if the proxy cache service's connect timeout (2 minutes, by default) is exceeded. (See "To View or Modify Timeouts" for a description of the Timeout for Server Connections property.)

A TCP connect call might fail because the operating system's timeout (3 minutes, by default) is exceeded or from some other cause. If the proxy cache service's timeout is shorter than the operating system's (as is true for the default case), the connect attempt is terminated before an error is returned, with the result that parent failover does not occur.

If your server experiences frequent connection timeouts when attempting to connect to a parent, you can set the proxy cache service's connect timeout to be at least 10 seconds greater than the operating system's TCP connect timeout. Alternatively, (if you have a serial connection to your server) you can reduce the operating system's timeout. To change the operating system's timeout, use the ndd command, which takes arguments in milliseconds. For example:

# ndd -set /dev/tcp tcp_ip_abort_cinterval 30000

The preceding command sets the TCP connect timeout to 30 seconds. To view the current TCP connect timeout, enter:

# ndd /dev/tcp tcp_ip_abort_cinterval

Rules for Pattern Matching for TTL Selection Property

Listed below are the rules for pattern matching used for the reg_expression component of the TTL Selection Based on URL property, described in "URL Policy". These rules are taken from Section 3C of the Solaris regexec man page.

1. If subexpression i in a regular expression is not contained within another subexpression, and it participated in the match several times, then the byte offsets in pmatch[i] will delimit the last such match.

2. If subexpression i is not contained within another subexpression, and it did not participate in an otherwise successful match, the byte offsets in pmatch[i] will be -1. A subexpression does not participate in the match when:

   • * or \{ \} appears immediately after the subexpression in a basic regular expression, or *, ?, or {} appears immediately after the subexpression in an extended regular expression, and the subexpression did not match (matched zero times)

     or

   • | is used in an extended regular expression to select this subexpression or another, and the other subexpression matched.

3. If subexpression i is contained within another subexpression j, and i is not contained within any other subexpression that is contained within j, and a match of subexpression j is reported in pmatch[j], then the match or non-match of subexpression i reported in pmatch[i] will be as described in 1. and 2. above, but within the substring reported in pmatch[j] rather than the whole string.

4. If subexpression i is contained in subexpression j, and the byte offsets in pmatch[j] are -1, then the pointers in pmatch[i] also will be -1.

5. If subexpression i matched a zero-length string, then both byte offsets in pmatch[i] will be the byte offset of the character or NULL terminator immediately following the zero-length string.