R: Lookup a hostname

nslookup {curl} | R Documentation

## Lookup a hostname

### Description

The `nslookup` function is similar to `nsl` but works on all platforms and can resolve ipv6 addresses if supported by the OS. Default behavior raises an error if lookup fails.

### Usage

    nslookup(host, ipv4_only = FALSE, multiple = FALSE, error = TRUE)

    has_internet()

### Arguments

`host` | a string with a hostname
`ipv4_only` | always return ipv4 address. Set to 'FALSE' to allow for ipv6 as well.
`multiple` | returns multiple ip addresses if possible
`error` | raise an error for failed DNS lookup. Otherwise returns `NULL`.

### Details

The `has_internet` function tests for internet connectivity by performing a dns lookup. If a proxy server is detected, it will also check for connectivity by connecting via the proxy.

### Examples

    # Should always work if we are online
    nslookup("www.r-project.org")

    # If your OS supports IPv6
    nslookup("ipv6.test-ipv6.com", ipv4_only = FALSE, error = FALSE)

[Package curl version 4.3.1 Index]